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					1.    The diagram shows the structure of a lithium atom.

                                                                                                                     KEY
                                                                                                                + = proton
                                                                                                                     = electron


                                                          +
                                                            +
                                                          +




      (a)    (i)       What is represented by                   .................................................................................

                                              +
                                                +
             (ii)      What is represented by + ...........................................................................
                                                                                                                                                            (2)

      (b)    What is the symbol for lithium? ................................................................................
                                                                                                                                                            (1)
                                                                                                                                                (Total 3 marks)



2.    The drawing shows a container of a compound called magnesium chloride.




      (i)    How many elements are joined together to form magnesium chloride?

             ....................................................................................................................................
                                                                                                                                                            (1)

      (ii)   Magnesium chloride is an ionic compound. What are the names of its ions?

             ................................................. ions and ................................................. ions
                                                                                                                                                            (1)




Bryngwyn School                                                                                                                                              1
      (iii)   How many negative ions are there in the formula for magnesium chloride?

              ....................................................................................................................................
                                                                                                                                                             (1)

      (iv)    Complete the sentence.

              Ions are atoms, or groups of atoms, which have lost or gained

              ......................................... .
                                                                                                                                                             (1)

      (v)     Suggest three properties which magnesium chloride has because it is an ionic compound.

              Property 1 ...................................................................................................................

              ....................................................................................................................................

              Property 2 ..................................................................................................................

              ....................................................................................................................................

              Property 3 ..................................................................................................................

              ....................................................................................................................................
                                                                                                                                                             (3)
                                                                                                                                                 (Total 7 marks)



3.    The diagram shows an atom.

                                                                                              ....................................A




         ...................................D                                                                       ....................................B




              ....................................C


      (a)     On the diagram, write the names of structures A, B, C and D.
                                                                                                                                                             (4)




Bryngwyn School                                                                                                                                               2
      (b)   To which Group of the periodic table does this atom belong?

            .....................................................................................................................................

            Give one reason for your answer.

            .....................................................................................................................................

            .....................................................................................................................................
                                                                                                                                                           (2)

      (c)   Name the element which is made up of this type of atom.

            .....................................................................................................................................
                                                                                                                                                           (1)
                                                                                                                                               (Total 7 marks)



4.    Sando-K is a medicine. It is given to people whose bodies contain too little of a particular element.

      Sando-K is a mixture of two compounds. The formulae of the two compounds are given below.

                                          KHCO3                                     KCl

      (a)   Use the Data Sheet to help you to name all the elements in these compounds.

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................
                                                                                                                                                           (3)

      (b)   Which metal do people given Sando-K need?

            .....................................................................................................................................
                                                                                                                                                           (1)
                                                                                                                                               (Total 4 marks)




Bryngwyn School                                                                                                                                             3
5.    (a)   Use the elements in the box to complete the table.

             aluminium               argon                    chlorine                     hydrogen                 lithium
             magnesium               oxygen                   silicon                      sulphur

            Write the name of the element that best matches each description. You may use each
            element once or not at all.

                                    Description                                                 Name of element

             This element is a low density metal
             that reacts quickly with water.

             This element is a reactive gas that
             when added to water makes a bleach.

             This element is an unreactive gas
             that is used in light bulbs.

             This element reacts with copper to
             form copper oxide.

             This element has the chemical
             symbol S.
                                                                                                                                                (5)

      (b)   The diagram shows the atomic structure of an atom of lithium.




            (i)    Label the diagram to show an electron, a neutron and a proton.
                                                                                                                                                (2)

            (ii)   What is the atomic number of lithium?

                   ..........................................................................................................................
                                                                                                                                                (1)




Bryngwyn School                                                                                                                                  4
      (c)       The diagrams show the electronic arrangement of the atoms of two elements.

                                                                   X                                                      –
                              –                                                                        –                  –                   –
                  –           –              –                                                              –             –              –


            –                                                                                  –      –                                        –


                  –           –             –                                                               –             –              –
                              –                                                                        –                  –                  –

                                                                                                                          –

                (i)    Name the part of the atoms labelled X.

                       ..........................................................................................................................
                                                                                                                                                           (1)

                (ii)   Why are these two elements in the same group of the Periodic Table?

                       ..........................................................................................................................

                       ..........................................................................................................................
                                                                                                                                                           (1)
                                                                                                                                              (Total 10 marks)



6.    The diagram shows a light bulb.




                                                                                                           Argon gas


                                       Metal
                                     filament




Bryngwyn School                                                                                                                                             5
      (a)   (i)       An argon atom has the structure shown. Use the words in the box to label the
                      particles in the atom. Each word should only be used once.

                                            electron                   neutron                   proton

                                                       8
                                                       8
                                                       2


                                                    18
                                                    22




                                                                                                                                                           (2)

            (ii)      Argon is unreactive. Why?

                      .....................................................................................................................

                      .....................................................................................................................
                                                                                                                                                           (1)

      (b)   Oxygen would not be a suitable gas to use in a light bulb. Explain why.

            ................................................................................................................................

            ................................................................................................................................
                                                                                                                                                           (2)
                                                                                                                                               (Total 5 marks)



7.    About 100 years ago a scientist called J. J. Thomson thought that an atom was a ball of positive
      charge with negative particles stuck inside. Today a different model is used. The diagram shows
      how an atom of carbon is represented by this model.




                                                                         +       +
                                                                               +
                                                                              + +
                                                                               +




Bryngwyn School                                                                                                                                             6
      (a)   The negative particles                   are called electrons.

            (i)       What is the name of the positive particles ?

                      ...........................................................................................................................
                                                                                                                                                           (1)

            (ii)      What particle is represented by ?                  
                      ...........................................................................................................................
                                                                                                                                                           (1)

            (iii)     What is the central part of the atom called that contains both  and ?                                      
                      ...........................................................................................................................
                                                                                                                                                           (1)

      (b)   Use the model to explain why the six electrons are arranged as shown.

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................
                                                                                                                                                           (2)
                                                                                                                                               (Total 5 marks)



8.    (a)   The diagram shows the atomic structure of an atom of lithium.




            (i)       Label the diagram to show an electron, a neutron and a proton.
                                                                                                                                                           (2)

            (ii)      What is the atomic number of lithium?

                      ..........................................................................................................................
                                                                                                                                                           (1)




Bryngwyn School                                                                                                                                             7
      (b)       The diagrams show the electron arrangement of the atoms of two elements.

                                                                      X                                                       –
                                 –                                                                        –                   –                  –
                  –              –              –                                                              –              –              –


            –                                                                                      –      –                                       –


                  –              –              –                                                              –              –             –
                                 –                                                                        –                   –                  –

                                                                                                                              –

                (i)       Name the part of the atoms labelled X.

                          ..........................................................................................................................
                                                                                                                                                               (1)

                (ii)      Why are these two elements in the same group of the Periodic Table?

                          ..........................................................................................................................

                          ..........................................................................................................................
                                                                                                                                                               (1)
                                                                                                                                                   (Total 5 marks)



9.    John Dalton wrote these statements in 1808.

               “All substances are made of a vast number of extremely small particles called atoms.”

               “Every particle of water is like every other particle of water, every particle of hydrogen is
                like every other particle of hydrogen, etc.”

      (a)       “Every particle of water is like every other particle of water.” Use Dalton‟s ideas and your
                knowledge of water to explain why.

                .....................................................................................................................................

                .....................................................................................................................................

                .....................................................................................................................................

                .....................................................................................................................................
                                                                                                                                                               (2)




Bryngwyn School                                                                                                                                                 8
      (b)   Dalton thought that all atoms of an element are exactly the same. We now know that it is
            possible to have atoms of the same element but with different mass numbers.
            The diagrams represent two atoms of hydrogen.



                                                               +                               +


                                                         Atom A                         Atom B

            (i)       State, in terms of particles, how these two atoms are different.

                      ..........................................................................................................................

                      ..........................................................................................................................
                                                                                                                                                           (1)

            (ii)      Complete this sentence by choosing the correct word from the box.

                        ions                         isotopes                         molecules                      protons

                      Atoms of the same element which have different mass numbers are called

                      ......................................................................... .
                                                                                                                                                           (1)
                                                                                                                                               (Total 4 marks)



10.   The diagram represents the electronic structure of an atom of an element.

                                                                      ×
                                                                      ×                             Nucleus



                                            ×                                                   ×


                                                                      ×
                                                                      ×
      The periodic table on the Data Sheet may help you with this question.

      (a)   Name this element.

            .....................................................................................................................................
                                                                                                                                                           (1)




Bryngwyn School                                                                                                                                             9
      (b)   Complete this sentence.

            The nucleus of an atom contains neutrons and ..........................................................
                                                                                                                              (1)
                                                                                                                  (Total 2 marks)



11.   (a)   The diagram represents an atom of beryllium. Use words from the box to label the
            diagram.


                        electron            ion        isotope molecule                   nucleus


                                              ×
                                              ×                 .......................................



                                              ×
                                              ×
                                                                .......................................
                                                                                                                              (2)

      (b)   Use crosses (x) to complete the diagram to show the electronic structure of a magnesium
            atom. The atomic (proton) number of magnesium is 12.




                                                                                                                              (2)
                                                                                                                  (Total 4 marks)




Bryngwyn School                                                                                                               10
12.   (a)   The diagram represents an atom.

            Choose words from the box to label the diagram.


                  electrode       electron          ion           molecule            nucleus


                                               ×
                                               ×              .....................


                                ×                           ×

                                               ×
                                               ×
                                                              .....................
                                                                                                            (2)

      (b)   When atoms react to form compounds, they become joined by chemical bonds.

            Complete the sentence about chemical bonds by crossing out the two incorrect words in
            the box.
                                                                                     electrons
            When atoms form chemical bonds, it involves giving, taking or sharing    neutrons     .
                                                                                     protons
                                                                                                            (1)
                                                                                                (Total 3 marks)



13.   Many foods contain chemical additives.

      (a)   A tin of creamed rice contains sodium carbonate as an acidity regulator.




            Sodium carbonate is an ionic compound which contains sodium ions (Na+) and carbonate
            ions (CO32–).

            Draw a ring around the formula of sodium carbonate.

                        NaCO3        Na2CO3         Na(CO3)2            Na(CO3)3
                                                                                                            (1)




Bryngwyn School                                                                                             11
      (b)   A tin of red kidney beans contains calcium chloride as a firming agent.




            Calcium chloride contains calcium ions (Ca2+) and chloride ions (Cl–).

            (i)    The diagram represents the electronic structure of a chlorine atom.

                                                    ××
                                                    ××
                                                    ×
                                                          ××
                                                          ××
                                              ×
                                             ××
                                                    ×
                                                    ××
                                                    ××
                   Four electronic structures are shown in the box.

                    A                    B                     C                          D

                   ××                                        ××
                   ××                  ××                    ××                          ××
                   ×                   ×                     ×                           ×
                        ××
                        ××



                                              ××




                                                                      ××
                                                                      ××




                                                                                               ××
            ××
            ××




                                  ××




                                                        ××




                                                                                    ××

                   ×
                   ××                  ×
                                       ××                    ×
                                                             ××                          ×
                                                                                         ××
                   ××                                        ××                          ××

                   Which electronic structure, A, B, C or D, represents a chloride ion (Cl–)?
                                                                                                                (1)

            (ii)   Complete the following sentence by crossing out the two words that are incorrect in
                   each box.

                                                                            gains               electrons
                    A calcium ion (Ca2+) is formed when a calcium           loses        two    neutrons    .
                    atom                                                    shares              protons
                                                                                                             (2)
                                                                                                 (Total 4 marks)




Bryngwyn School                                                                                                 12
14.   Magnesium oxide is a compound, made up of magnesium ions and oxide ions.

                                                                    Mg O Mg
                                                                     O Mg O
                                                                    Mg O Mg

      (a)   What is the charge on each magnesium ion? .............................................................
                                                                                                                                                           (1)

      (b)   Explain how the magnesium ions get this charge.

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................
                                                                                                                                                           (2)
                                                                                                                                               (Total 3 marks)



15.   The two carbon atoms represented below are isotopes.

                                          ISOTOPE 1.                                          ISOTOPE 2.

                                                   14              mass number                         12
                                                        C                                                   C
                                                    6             proton number                         6


      (a)   Describe two ways in which the isotopes are similar.

            .....................................................................................................................................

            .....................................................................................................................................
                                                                                                                                                           (2)

      (b)   Describe as fully as you can one way in which they are different.

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................
                                                                                                                                                           (2)
                                                                                                                                               (Total 4 marks)




Bryngwyn School                                                                                                                                            13
16.   You will find it helpful to use the information on the Data Sheet when answering this question.

      In the nucleus of an aluminium atom are:

                                                               13 protons
                                                     and       14 neutrons.

      (a)   Complete these sentences.

            (i)       The mass number of the aluminium atom is ...................................... .

            (ii)      In an atom of aluminium there are ....................................... electrons.
                                                                                                                                                           (2)

      (b)   Why is an aluminium atom electrically neutral?

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................
                                                                                                                                                           (2)

      (c)   Complete the table for the element fluorine.


                                                   NUMBER OF                         NUMBER OF                     NUMBER OF
                      PARTICLE                      PROTONS                          NEUTRONS                      ELECTRONS

                    Fluorine atom                             9                                                               9

                    Fluoride ion                                                               10

                                                                                                                                                           (3)
                                                                                                                                               (Total 7 marks)



17.   Atoms of calcium, phosphorus and fluorine are represented below, each with its mass
      number and proton number.

                                   40              31              19                            mass numbers
                                        Ca              P               F
                                   20              15              9                             proton numbers

      (a)   Use this information to complete the table.


                                                                  CALCIUM                  PHOSPHORUS                     FLUORINE

       Number of protons in the nucleus                                  20                                                        9

       Number of neutrons in the nucleus                                 20                           16

       Number of electrons                                                                            15                           9
                                                                                                                                                           (3)



Bryngwyn School                                                                                                                                            14
      (b)   Calcium and fluorine atoms can combine to form the compound calcium fluoride, CaF2.

            The fluoride ion is represented by F–.

            (i)     Explain how the fluorine atom forms a fluoride ion.

                    ..........................................................................................................................

                    ..........................................................................................................................
                                                                                                                                                        (2)

            (ii)    How is the calcium ion represented?

                    ..........................................................................................................................
                                                                                                                                                        (2)

      (c)   Phosphorus and fluorine form a covalent compound, phosphorus trifluoride.

            Complete the sentences below which are about this compound.

            Phosphorus trifluoride is made up of phosphorus and fluorine ................................

            These are joined together by sharing pairs of ............................................... to form

            phosphorus trifluoride ........................................................ .
                                                                                                                                                        (3)

      (d)   (i)     Sodium chloride, an ionic compound, has a high melting point whereas paraffin
                    wax, a molecular compound, melts easily.

                    Explain why.

                    ..........................................................................................................................

                    ..........................................................................................................................

                    ..........................................................................................................................

                    ..........................................................................................................................
                                                                                                                                                        (2)

            (ii)    Molten ionic compounds conduct electricity but molecular compounds are non-
                    conductors, even when liquid.

                    Explain why.

                    ..........................................................................................................................

                    ..........................................................................................................................

                    ..........................................................................................................................
                                                                                                                                                        (2)
                                                                                                                                           (Total 14 marks)




Bryngwyn School                                                                                                                                         15
18.   (a)   The diagrams below show the electronic structure of a magnesium atom and a
            magnesium ion.

                              magnesium atom                                                               magnesium ion




                                                                             KEY

                                                                         = electron

            What is the charge on the magnesium ion? ...............................................................
                                                                                                                                                           (2)

      (b)   Calcium bromide has the formula CaBr2.

            What does this tell you about the ions in this compound?

            ....................................................................................................................................

            ....................................................................................................................................
                                                                                                                                                           (2)
                                                                                                                                               (Total 4 marks)



19.   (a)   Write down the symbols for

            lithium ................................................................................

            fluorine ...............................................................................
                                                                                                                                                           (2)




Bryngwyn School                                                                                                                                            16
      (b)   The electronic structure of a lithium atom can be shown like this:




                   2,1 or                                       where x is an electron.




            In a similar way, complete this diagram to show the electronic structure of a
            fluorine atom.




                   2,7 or



                                                                                                                       (1)

      (c)   A lithium atom can lose one electron to form a lithium ion which can be written (2)+
            A fluorine atom can gain one electron to form a fluoride ion.

            Choose from the list the correct way to write the fluoride ion.

                               (2,6)+     (2,7)+    (2,7)-    (2,8)+       (2,8)–

                                                              Answer ..........................................
                                                                                                                       (2)
                                                                                                           (Total 5 marks)




Bryngwyn School                                                                                                        17
20.   The chart shows the processes involved in the manufacture of nitric acid from ammonia.


                                                                                      gases at 300ºC                             layers of
                                                                                                                                 platinum gauze



                                                                                                                first reaction
                                                                                                                vessel
       ammonia                                                                                                                                ?
                                                                Heat
       oxygen                                                   exchanger


                                                nitrogen
                                                monoxide




       oxygen                                             Cooler


                                                                                                                                        nitric acid

      (a)   Complete the word equation for the reaction that takes place in the first reaction vessel.

                    ammonia + ......................................                           nitrogen monoxide + water
                                                                                                                                                      (1)

      (b)   What is the use of the platinum gauze in the reaction vessel?

            .....................................................................................................................................
                                                                                                                                                      (1)

      (c)   To convert nitrogen monoxide into nitric acid, two further reactants are needed.
            What are they?

            ................................................................ and ............................................................
                                                                                                                                                      (1)

      (d)   Complete the word equation below, to show how to make the fertiliser, ammonium
            nitrate.

            ................................ + .........................                  ammonium nitrate + water
                                                                                                                                                      (2)




Bryngwyn School                                                                                                                                       18
      (e)    Calculate the percentage of nitrogen in the fertiliser, ammonium nitrate NH4NO3.

             .....................................................................................................................................

             .....................................................................................................................................

             .....................................................................................................................................

             .....................................................................................................................................
                                                                                                                                                            (2)
                                                                                                                                                (Total 7 marks)



21.   Electrons, neutrons and protons are sub-atomic particles.

      (a)    Complete the six spaces in the following table.

              Name of sub-atomic                                         Relative mass                                         Relative charge
                   particle


            .......................................                                 1                                   ........................................


            .......................................              ........................................                                  0

                                                                                  1
            .......................................                             1840                                    .........................................

                                                                                                                                                                    (3)

      (b)    An aluminium atom has 13 electrons. How are these arranged in shells around the
             nucleus?

             ....................................................................................................................................
                                                                                                                                                                    (1)

      (c)    Chromium atoms have 24 protons and 28 neutrons.

             (i)       How many electrons does each neutral chromium atom have?

                       ...........................................................................................................................
                                                                                                                                                                    (1)

             (ii)      What is the mass number of chromium?

                       ...........................................................................................................................
                                                                                                                                                                    (1)

      (d)    What change occurs to an atom which undergoes the process of reduction in a chemical
             reaction?

             ....................................................................................................................................

             ....................................................................................................................................
                                                                                                                                                                    (1)

Bryngwyn School                                                                                                                                                     19
      (e)   The diagram shows part of the ionic lattice of a sodium chloride crystal.




                                                                                                             Sodium ion
                                                                                                             Chloride ion


            Explain why the ions in this lattice stay in place.

            ....................................................................................................................................

            ....................................................................................................................................

            ....................................................................................................................................

            ....................................................................................................................................

            ....................................................................................................................................

            ....................................................................................................................................
                                                                                                                                                          (3)
                                                                                                                                             (Total 10 marks)



22.   (a)   Atoms are made of sub-atomic particles. Complete the six spaces in the table.

                                    Name of sub-atomic                          Relative mass                        Relative charge
                                         particle
                                                                                         1
                                    .................................                  1840                            ......................

                                              Neutron                            .....................                 .......................

                                    .................................                     1                            .......................

                                                                                                                                                          (3)




Bryngwyn School                                                                                                                                           20
      (b)   Complete the spaces in the sentences.

            (i)     The atomic number of an atom is the number of ..................................... in its

                    nucleus and is equal to the number of ..................................................... if the

                    atom is not charged.
                                                                                                                                                        (1)

            (ii)    The mass number of an atom is the total number of ................................. and

                    ...................................... in its nucleus.
                                                                                                                                                        (1)

      (c)   The table gives information about the atoms of three elements.

                                                                                  Number of electrons in:
                            Name                   Chemical
                              of                    symbol                     1st                2nd                  3rd
                           element                                            shell               shell               shell

                          Fluorine                        F                      2                    7                  0

                            Neon                         Ne                      2                    8                  0

                           Sodium                        Na                      2                    8                  1


            Two of these elements can react together to form a chemical compound.

            (i)     What is the name and the formula of this compound?

                    Name ................................................... Formula ..........................................
                                                                                                                                                        (2)

            (ii)    What type of bonding holds this compound together?

                    ...........................................................................................................................
                                                                                                                                                        (1)

            (iii)   Explain, in terms of electron transfer, how the bonding occurs in this compound.

                    ...........................................................................................................................

                    ...........................................................................................................................

                    ...........................................................................................................................

                    ...........................................................................................................................

                    ...........................................................................................................................

                    ...........................................................................................................................
                                                                                                                                                        (2)
                                                                                                                                           (Total 10 marks)




Bryngwyn School                                                                                                                                         21
23.   The table gives information about the atoms of three elements.

                                                                              Number of electrons in:
            Name of               Chemical
            element                symbol
                                                                 1st shell                        2 nd shell                       3 rd shell

            Fluorine                     F                           2                                  7                               0

             Neon                       Ne                           2                                  8                               0

            Sodium                      Na                           2                                  8                               1

      Two of these elements can react together to form a chemical compound.

      (a)    What is the name and the formula of this compound?

             Name ...........................................................................................................................

             Formula .......................................................................................................................
                                                                                                                                                            (2)

      (b)    What type of bonding holds this compound together?

             .....................................................................................................................................
                                                                                                                                                            (1)
                                                                                                                                                (Total 3 marks)



24.   Use the Periodic Table of Elements on the Data Sheet to help you to answer this question.

      (a)    Describe, in as much detail as you can, the structure of a fluorine atom.

             .....................................................................................................................................

             .....................................................................................................................................

             .....................................................................................................................................

             .....................................................................................................................................

             .....................................................................................................................................

             .....................................................................................................................................
                                                                                                                                                            (3)




Bryngwyn School                                                                                                                                             22
      (b)   Complete the diagram to show the electronic structure of a magnesium atom.




                                                    Mg




                                                                                                         (1)
                                                                                             (Total 4 marks)



25.   This question is about sodium chloride (common salt) which is an important chemical.

      Sodium chloride can be made by burning sodium in chlorine gas.




      (a)   Balance the symbol equation for the reaction of sodium with chlorine.

                       Na(s)    +       Cl2(g)                    NaCl(s)
                                                                                                         (1)




Bryngwyn School                                                                                          23
      (b)   (i)    Complete the diagrams below to show the electronic structures of a sodium and a
                   chlorine atom. (Atomic number of sodium = 11 and chlorine = 17.)




                                   Na                                                                            Cl




                               Sodium                                                                      Chlorine
                                                                                                                                                 (3)

            (ii)   When sodium reacts with chlorine the sodium atoms are changed into sodium ions
                   (Na+) and the chlorine atoms are changed into chlorine ions (Cl–).

                   Explain how:

            1.     a sodium atom changes into a sodium ion;

                   ...........................................................................................................................

                   ...........................................................................................................................
                                                                                                                                                 (2)

            2.     a chlorine atom changes into a chloride ion.

                   ...........................................................................................................................

                   ...........................................................................................................................
                                                                                                                                                 (2)

      (c)   The element potassium is in the same group of the Periodic Table as sodium. Potassium
            reacts with chlorine to make potassium chloride which is sometimes used instead of
            common salt in cooking.

            (i)    Predict the formula of potassium chloride.

                   ...........................................................................................................................
                                                                                                                                                 (1)

            By reference to the electronic structures of potassium and sodium explain:

            (ii)   Why the reaction of potassium with chlorine is similar to the reaction of sodium
                   with chlorine.

                   ...........................................................................................................................

                   ...........................................................................................................................
                                                                                                                                                 (1)


Bryngwyn School                                                                                                                                  24
      (d)    The electrolysis of sodium chloride solution is an important industrial process. The
             diagrams below show two experiments set up during an investigation of the electrolysis of
             sodium chloride.

                                                                                                                       sodium chloride
                                     + –                                                                               solution

                                                              A

                                                                                                                         A
            solid sodium
            chloride                                                                            + –


                           Experiment 1                                                   Experiment 2

             (i)    What would be the reading on the ammeter in experiment 1?

                    .................................................... A

             (ii)   Explain your answer.

                    ...........................................................................................................................

                    ...........................................................................................................................

                    ...........................................................................................................................
                                                                                                                                                  (3)

      (e)    The equations below show the reactions which take place in experiment 2.

                                        H2O(1)                              H+(aq)         +         OH– (aq)

                                        2H+(aq)              +               2e–                     H2(g)

                                        2Cl–(aq)             –               2e–                     Cl2(g)

             (i)    Which substance provides hydrogen ions?

                    ...........................................................................................................................
                                                                                                                                                  (1)




Bryngwyn School                                                                                                                                   25
            (ii)      Name the product formed at:

                      (A)       the positive electrode;

                      ...........................................................................................................................

                      (B)       the negative electrode.

                      ...........................................................................................................................
                                                                                                                                                          (1)
                                                                                                                                             (Total 15 marks)



26.   There are millions of different substances that make up our world. All these substances are made
      from chemical elements.

      (a)   What is an element?

            .....................................................................................................................................

            .....................................................................................................................................
                                                                                                                                                           (1)

      (b)   Many substances are compounds. What is a compound?

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................
                                                                                                                                                           (2)
                                                                                                                                               (Total 3 marks)



27.   (a)   The list below gives six substances.

                  aluminium
                  beer
                  copper
                  milk
                  pure water
                  sodium chloride

            Put each substance in the correct column of the table.

                       ELEMENTS                               COMPOUNDS                                  MIXTURES




                                                                                                                                                           (3)
      (b)   Elements can be divided into two groups, metals and non-metals.

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            The list below gives some properties of elements.
                 brittle
                 can be hammered into shape
                 dull
                 good conductors of electricity
                 poor conductors of electricity
                 shiny

            Put each property into the correct column.

                   PROPERTIES OF METALS              PROPERTIES OF NON-METALS




                                                                                         (Total 3 marks)



28.   The diagram represents an atom. Choose words from the list to label the diagram.

                     electron           ion          neutron             nucleus




                             proton

                                                                                         (Total 3 marks)




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29.   Most of the cans used for drinks are made from aluminium.




      (a)   (i)     Aluminium is an element. What does this mean?

                    ...........................................................................................................................

                    ...........................................................................................................................
                                                                                                                                                  (1)

            (ii)    Metals are malleable and this makes them suitable to make drinks cans. What does
                    malleable mean?

                    ...........................................................................................................................

                    ...........................................................................................................................
                                                                                                                                                  (1)

      (b)   The arrangement of electrons in an aluminium atom is:
                                                                         –
                                                                         –
                                                          –              –             –


                                                     –                                      –     –


                                                          –              –             –
                                                                         –
                                                                         –              Aluminium
                                                                                           atom

            (i)     On the diagram label the nucleus of the aluminium atom.
                                                                                                                                                  (1)

            (ii)    How many protons does an aluminium atom have?

                    ...........................................................................................................................
                                                                                                                                                  (1)

            (iii)   To which group of the Periodic Table does aluminium belong?

                    ...........................................................................................................................
                                                                                                                                                  (1)



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            (iv)    To which period of the Periodic Table does aluminium belong?

                    ...........................................................................................................................
                                                                                                                                                        (1)

      (c)   The reaction between aluminium and iron oxide is used to join lengths of railway track. It
            is called the thermit reaction.

                                          Fe2O3(s) + 2Al(s)  Al2O3(s) + 2Fe(l)

            (i)     Why does aluminium react with iron oxide?

                    ...........................................................................................................................
                                                                                                                                                        (1)

            (ii)    What does the (1) after Fe in the chemical equation mean?

                    ...........................................................................................................................
                                                                                                                                                        (1)

            (iii)   Suggest why the thermit reaction can be used to join lengths of railway track.

                    ...........................................................................................................................

                    ...........................................................................................................................

                    ...........................................................................................................................

                    ...........................................................................................................................
                                                                                                                                                        (2)
                                                                                                                                           (Total 10 marks)



30.   Lithium is a very reactive metal.

      (a)   Lithium reacts with cold water.




                                                                                             Lithium




                                                                                             Water with universal
                                                                                             indicator solution



            (i)     Which physical property of lithium is seen during this reaction?

                    ..........................................................................................................................
                                                                                                                                                        (1)




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            (ii)    Which chemical property of lithium will be shown by the universal indicator?

                    ..........................................................................................................................
                                                                                                                                                        (1)

      (b)   Complete the sentence by writing in the missing numbers.

            Lithium has an atomic number of 3 and a mass number of 7.

            This means that an atom of lithium has .................... protons .................... electrons

            and ....................... neutrons.
                                                                                                                                                        (3)
                                                                                                                                            (Total 5 marks)



31.   (a)   Use the information given about a sodium atom to complete the table.


                                                                                   the number of protons is
                   mass number                                 In one
                                23                                                 the number of neutrons is
                                   Na                          atom of
                                11
                   proton number                               sodium
                                                                                   the number of electrons is
                                                                                                                                                        (3)

      (b)   Sodium carbonate reacts with acids.

            (i)     Complete the word equation.

            sodium carbonate + hydrochloric acid  sodium chloride + ...................... + water
                                                                                                                                                        (1)

            (ii)    Name the salt produced if sodium carbonate reacts with dilute nitric acid.

                    ...........................................................................................................................
                                                                                                                                                        (1)
                                                                                                                                            (Total 5 marks)



32.   (a)   The diagrams represent the atomic structures of two gases, hydrogen and helium.

                                                                                                             x = an electron
                                                                                                             p = a proton
                                                                                                             n = a neutron


                                                                                     2p
                                                                                     2n



                            hydrogen                                              helium

            Hydrogen gas is made up of diatomic molecules (molecules with two atoms).
            Helium gas exists as single atoms.

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            (i)        How is a molecule of hydrogen formed from two hydrogen atoms?
                       (You may use a diagram as part of your answer)

                       ...........................................................................................................................

                       ...........................................................................................................................

                       ...........................................................................................................................
                                                                                                                                                           (2)

            (ii)       Why does helium exist only as single atoms?

                       ...........................................................................................................................

                       ...........................................................................................................................

                       ...........................................................................................................................
                                                                                                                                                           (2)

      (b)   Hydrogen combines with carbon to form methane.
            Each molecule contains four hydrogen atoms strongly bonded to a carbon atom.

                                                                                                                      structural formula
                    methane molecules                                                                                 of methane CH 4
                                                                                                      H
             H                          H
             H




                                        H




                       H                         H
             H     C                    H   C                                           H             C             H
                       H                         H
                           H                         H
                           H




                                                     H




                                    H                         H

                           H   C                     H   C                                            H
                                    H                         H


            Explain why methane has a low boiling point.

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................
                                                                                                                                                           (2)
                                                                                                                                               (Total 6 marks)



33.   (a)   Copper is a metal.
            Explain how it conducts electricity.

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................
                                                                                                                                                           (2)




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      (b)   Graphite is a non-metal.




            Use the information to explain why graphite conducts electricity.

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................
                                                                                                                                                            (3)
                                                                                                                                                (Total 5 marks)



34.   The diagram shows part of the ionic lattice of a sodium chloride crystal.




            (i)       Complete the spaces in the table to give information about both of the ions in this
                      lattice.

                                          Name of ion                                                       Charge

                          .....................................................         .....................................................

                          .....................................................         .....................................................
                                                                                                                                                            (2)

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            (ii)    When it is solid, sodium chloride will not conduct electricity. However, molten
                    sodium chloride will conduct electricity. Explain this difference.

                    ..........................................................................................................................

                    ..........................................................................................................................

                    ..........................................................................................................................

                    ..........................................................................................................................
                                                                                                                                                 (2)

            (iii)   Complete the sentence.

                    Sodium chloride conducts electricity when it is molten and when it is

                    ..........................................................................................................................
                                                                                                                                                 (1)

      (b)   The symbol for a calcium atom can be shown like this:

                                                                 40
                                                                 20
                                                                        Ca
            (i)     What is the mass number of this atom?

                    ..........................................................................................................................
                                                                                                                                                 (1)

            (ii)    What information is given by the mass number?

                    ..........................................................................................................................

                    ..........................................................................................................................
                                                                                                                                                 (1)

      (c)   Calcium burns in oxygen with a brick-red flame. The product is a white solid. It is
            calcium oxide and its formula is CaO.

            (i)     Balance the chemical equation for the reaction.

                                        Ca(s) +                   O2(g)                         CaO(s)
                                                                                                                                                 (1)




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            (ii)    Describe, in terms of electrons, what happens to a calcium atom when it becomes a
                    calcium ion.

                    ..........................................................................................................................

                    ..........................................................................................................................

                    ..........................................................................................................................

                    ..........................................................................................................................
                                                                                                                                                        (2)
                                                                                                                                           (Total 10 marks)



35.   Fluorine is the most reactive element in group 7 of the Periodic Table.
      Fluorine reacts with all the other elements in the Periodic Table except some of the noble gases.
      It does not react with helium, neon and argon, but it does react with xenon. Many substances
      burst into flames when exposed to fluorine.

      (a)   (i)     The electronic structure of chlorine is 2.8.7. What is the electronic structure
                    of fluorine?

                    ..........................................................................................................................
                                                                                                                                                        (1)

            (ii)    What is the electronic structure of the chloride ion Cl–?

                    ..........................................................................................................................
                                                                                                                                                        (1)

            (iii)   Explain why fluorine is more reactive than chlorine.

                    ..........................................................................................................................

                    ..........................................................................................................................

                    ..........................................................................................................................

                    ..........................................................................................................................

                    ..........................................................................................................................
                                                                                                                                                        (4)
      (b)   (i)     What does the information at the start of this question suggest about the reactivity of
                    the elements in group 0?


                    ..........................................................................................................................

                    ..........................................................................................................................
                                                                                                                                                        (1)




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            (ii)    A chemist did an experiment to find out if fluorine reacts with xenon. The two
                    gases were mixed in a glass container. The only product detected was silicon
                    fluoride. Explain what happened.

                    ..........................................................................................................................

                    ..........................................................................................................................

                    ..........................................................................................................................
                                                                                                                                                        (2)

            (iii)   The experiment was repeated many years later but the gases were mixed in a
                    different type of container. A white solid was obtained which was xenon fluoride.

                    Predict whether you think (1) krypton and (2) radon will react with fluorine.
                    Explain the reasons for your predictions.

                    ..........................................................................................................................

                    ..........................................................................................................................

                    ..........................................................................................................................

                    ..........................................................................................................................

                    ..........................................................................................................................

                    ..........................................................................................................................
                                                                                                                                                        (5)
                                                                                                                                           (Total 14 marks)



36.   Use the Periodic Table on the Data Sheet to help you to answer this question.

      (a)   State one similarity and one difference in the electronic structure of the elements:

            (i)     across the Period from sodium to argon;

                    ...........................................................................................................................

                    ...........................................................................................................................

                    ...........................................................................................................................
                                                                                                                                                        (2)

            (ii)    down Group 7 from fluorine to astatine.

                    ...........................................................................................................................

                    ...........................................................................................................................

                    ...........................................................................................................................
                                                                                                                                                        (2)




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      (b)   (i)       State the trend in reactivity of the Group 1 elements.

                      ...........................................................................................................................
                                                                                                                                                          (1)

            (ii)      Explain this trend in terms of atomic structure.

                      ...........................................................................................................................

                      ...........................................................................................................................

                      ...........................................................................................................................

                      ...........................................................................................................................

                      ...........................................................................................................................
                                                                                                                                                          (3)

      (c)   Hydrogen is an element which is difficult to fit into a suitable position in the Periodic
            Table. Give reasons why hydrogen could be placed in either Group 1 or Group 7.

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................
                                                                                                                                                          (3)
                                                                                                                                             (Total 11 marks)



37.   (a)   The electronic structure of a sodium atom can be written 2,8,1.
            Write the electronic structure of a potassium atom in the same way.

            .....................................................................................................................................
                                                                                                                                                          (1)

      (b)   The electronic structure of a sodium atom can also be represented as in the
            diagram below.




                                                                                          sodium
                                                                     Na                   atom




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            (i)    Draw a similar diagram for a fluorine atom.




            (ii)   Draw similar diagrams to show the electronic structure of the particles in
                   sodium fluoride.




                                                                                                            (4)
                                                                                                (Total 5 marks)



38.   The diagram represents the structure of graphite.




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      Use your knowledge and understanding of the structure of graphite to explain why graphite
      can be used:

      (a)       in the „leads‟ of pencils;

                ....................................................................................................................................

                ....................................................................................................................................

                ....................................................................................................................................

                ....................................................................................................................................

                ....................................................................................................................................

                ....................................................................................................................................

                ....................................................................................................................................

      (b)       as an electrical conductor.

                ....................................................................................................................................

                ....................................................................................................................................

                ....................................................................................................................................

                ....................................................................................................................................

                ....................................................................................................................................

                ....................................................................................................................................

                ....................................................................................................................................
                                                                                                                                                   (Total 5 marks)



39.   Bromine can be made from sea water. In 1000 g of sea water there is 0.065 g of bromine.
      What mass of sea water would be needed to make 1000 g of bromine?

      ...............................................................................................................................................

      ...............................................................................................................................................
                                                                                                                                                   (Total 2 marks)




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40.   The diagrams show three isotopes of potassium.




                      19                                                     19                                                     19
                      20                                                     21                                                     22




                                                                          Key
                                          Proton                       Neutron                         Electron

      (i)    In what way does the atomic structure show you that they are all atoms?

             .....................................................................................................................................

             .....................................................................................................................................
                                                                                                                                                            (1)

      (ii)   Explain why these three atoms are called isotopes of potassium.

             .....................................................................................................................................

             .....................................................................................................................................

             .....................................................................................................................................

             .....................................................................................................................................

             .....................................................................................................................................

             .....................................................................................................................................
                                                                                                                                                            (3)
                                                                                                                                                (Total 4 marks)




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41.   Brine, a solution containing sodium chloride in water, can be used to manufacture chlorine,
      hydrogen and sodium hydroxide. A student sets up a simplified model of the industrial cell.


                               Chlorine                                                                Hydrogen




                                                                                                      Brine




      (a)   The electron arrangements of some atoms are shown here.

                                                 H            1

                                                 O            2.6

                                                 Na           2.8.1

                                                 C1           2.8.7

            (i)    Use the relevant electron arrangements to describe the bonding in water.

                   ...........................................................................................................................

                   ...........................................................................................................................

                   ...........................................................................................................................

                   ...........................................................................................................................

                   ...........................................................................................................................

                   ...........................................................................................................................
                                                                                                                                                 (2)

            (ii)   Use the relevant electron arrangements to describe the bonding in sodium chloride.

                   ...........................................................................................................................

                   ...........................................................................................................................

                   ...........................................................................................................................

                   ...........................................................................................................................

                   ...........................................................................................................................

                   ...........................................................................................................................
                                                                                                                                                 (3)

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      (b)   As electricity passes through the brine the pH starts to increase. Explain why.

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................
                                                                                                                                                          (2)

                                                          35              37
      (c)   Use the atomic structures of                  17 Cl    and    17 Cl    to explain the meaning of the term isotopes.

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................
                                                                                                                                                          (3)
                                                                                                                                             (Total 10 marks)



42.   Caesium is an element in Group 1 of the periodic table.

      (a)   Which of the electronic structures represented by A to D is correct for a caesium atom?
            The periodic table on the Data Sheet may help you to answer this question.

                                                                  Electronic structure
                                                     A              2, 8, 18, 18, 8, 1
                                                     B              2, 8, 18, 18, 9
                                                     C              2, 8, 18, 27
                                                     D              2, 8, 18, 18, 6, 3

            The electronic structure for a caesium atom is represented by letter .........................
                                                                                                                                                          (1)




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      (b)   When a small piece of lithium is added to cold water it fizzes around on the surface of the
            water. A small piece of caesium explodes when added to water.

            Explain in terms of electronic structure why a caesium atom is more reactive than a
            lithium atom.

            .....................................................................................................................................

            .....................................................................................................................................
                                                                                                                                                           (2)
                                                                                                                                               (Total 3 marks)




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