Naming compounds ???????????????????? ?? by tIvg6Hb

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									CHEMISTRY
Revision guide
for IGCSE




       Written by Shane Sun

       For 2009 – 2010 examinations
Introduction
This book is for IGCSE level only and the practical work is not mentioned in

this book.



Each section starts with a list of learning objectives, which are directly related

to the CIE syllabus. Questions throughout the text reinforce students’

understanding and offer excellent opportunities for independent study.
                                                       CONTENTS
                                                       CONTENTS
Preparing for IGCSE chemistry ............................................................................................ 1
    Section 1 Naming inorganic compounds ....................................................................... 1
        Naming elements .................................................................................................... 1
        Naming compounds ................................................................................................ 1
Unit 1 BONDING AND STRUCTURE .................................................................................. 4
    Section 1 States of matters ............................................................................................ 4
        Arrangement and movement of the particles in each of the three states ................. 4
        Changes of state ..................................................................................................... 5
        Diffusion .................................................................................................................. 5
        Questions ................................................................................................................ 6
    Section 2 Atomic structure ........................................................................................... 17
        Atomic structure .................................................................................................... 17
        Isotopes ................................................................................................................. 18
        Electronic configurations ....................................................................................... 18
        Questions .............................................................................................................. 19
    Section 3 Chemical bonding ........................................................................................ 28
        Distingwish of substances ..................................................................................... 29
        Chemical bonding.................................................................................................. 29
        Metallic bonds ....................................................................................................... 30
        Ionic bonds ............................................................................................................ 31
        Covalent bonds ..................................................................................................... 34
        Summary ............................................................................................................... 38
        Questions .............................................................................................................. 39
Unit 2 PERIODIC TABLE 1 .............................................. Error! Bookmark not defined.67
    Section 1 Energy transfering in chemical reactions ... Error! Bookmark not defined.67
        Energy transfering in chemical reactions ............. Error! Bookmark not defined.67
        Structure of the Periodic Table ............................ Error! Bookmark not defined.68
        Questions ............................................................ Error! Bookmark not defined.69
    Section 2 Group properties ........................................ Error! Bookmark not defined.82
        Group 1 elements – alkali metals ........................ Error! Bookmark not defined.82
        Group VII elements – halogens ........................... Error! Bookmark not defined.83
        Group 0 elements – noble gases......................... Error! Bookmark not defined.83
        Questions ............................................................ Error! Bookmark not defined.84
    Section 3 Metals ...................................................... Error! Bookmark not defined.104
        Common properties of metals ........................... Error! Bookmark not defined.105
        Reactivity series ................................................ Error! Bookmark not defined.105
        Extraction of metals ........................................... Error! Bookmark not defined.106
        Uses of some common metals and alloys ......... Error! Bookmark not defined.108
        Transition elements ........................................... Error! Bookmark not defined.108
        Questions .......................................................... Error! Bookmark not defined.110
Unit 3 WATER AND AIR ................................................. Error! Bookmark not defined.153
    Section 1 Treatment of water supply ....................... Error! Bookmark not defined.153
        Purification of the water supply.......................... Error! Bookmark not defined.153
        Uses of water .................................................... Error! Bookmark not defined.154
        Chemical test for water ...................................... Error! Bookmark not defined.154
        Questions .......................................................... Error! Bookmark not defined.154
    Section 2 Air ............................................................ Error! Bookmark not defined.162
        Composition of clean air .................................... Error! Bookmark not defined.162
        Uses of nobles gases ........................................ Error! Bookmark not defined.163
        Uses of oxygen.................................................. Error! Bookmark not defined.163
        Common pollutants in the air ............................. Error! Bookmark not defined.164
        Formation of carbon dioxide .............................. Error! Bookmark not defined.164
        Questions .......................................................... Error! Bookmark not defined.165
        Core .................................................................. Error! Bookmark not defined.170
    Section 3 Rusting prevention ................................... Error! Bookmark not defined.179
        Methods of rusting prevention ........................... Error! Bookmark not defined.179
        Questions .......................................................... Error! Bookmark not defined.180
Unit 4 ACIDS AND BASES ............................................ Error! Bookmark not defined.186
    Section 1 Acids and bases....................................... Error! Bookmark not defined.186
        Common properties of acids and bases ............ Error! Bookmark not defined.186
        Theories of acids and bases ............................. Error! Bookmark not defined.187
        Weak and strong acids/bases ........................... Error! Bookmark not defined.188
        Types of oxides ................................................. Error! Bookmark not defined.189
        Questions .......................................................... Error! Bookmark not defined.190
    Section 2 Manufacture and uses of lime .................. Error! Bookmark not defined.203
        Lime .................................................................. Error! Bookmark not defined.203
        Uses of limestone .............................................. Error! Bookmark not defined.204
        Questions .......................................................... Error! Bookmark not defined.204
    Section 3 Making salts ............................................. Error! Bookmark not defined.215
        Preparing NaCl by titration ................................ Error! Bookmark not defined.215
        Making dry pure CuSO4 crystal ( CuSO4 . 5H2O )Error!                                Bookmark        not
        defined.215
        Making BaSO4 by precipitation. ......................... Error! Bookmark not defined.215
        Questions .......................................................... Error! Bookmark not defined.216
Unit 5 PRACTICAL SKILL .............................................. Error! Bookmark not defined.227
    Section1 Separation of mixtures .............................. Error! Bookmark not defined.227
        Questions .......................................................... Error! Bookmark not defined.227
    Section2 Test for ions .............................................. Error! Bookmark not defined.242
        Questions .......................................................... Error! Bookmark not defined.242
Unit 6 AMOUNT OF SUBSTANCES .............................. Error! Bookmark not defined.252
        Ionic equation and word equation...................... Error! Bookmark not defined.252
        Number of moles ............................................... Error! Bookmark not defined.252
        Ar and Mr ........................................................... Error! Bookmark not defined.254
        Questions .......................................................... Error! Bookmark not defined.254
Unit 7 REDOX AND ELECTROCHEMISTRY ................ Error! Bookmark not defined.262
    Section 1 Redox reaction......................................... Error! Bookmark not defined.262
        Definitions of oxidation and reduction................ Error! Bookmark not defined.262
        Relationship between reduction and oxidation .. Error! Bookmark not defined.262
        Questions .......................................................... Error! Bookmark not defined.263
    Section 2 Electrochemistry ...................................... Error! Bookmark not defined.265
        Cell .................................................................... Error! Bookmark not defined.265
        Electrolysis ( Using inert electrodes) ................. Error! Bookmark not defined.266
        Electroplating and purification of copper ........... Error! Bookmark not defined.269
        The extraction of aluminium from molten aluminium oxide/cryolite ................. Error!
        Bookmark not defined.270
        Questions .......................................................... Error! Bookmark not defined.271
Unit 8 PERIODIC TABLE 2 ............................................ Error! Bookmark not defined.301
    Section 1 Rate of reaction ....................................... Error! Bookmark not defined.301
        Measure the rate of reactions ............................ Error! Bookmark not defined.301
        Collision theory .................................................. Error! Bookmark not defined.302
        Summary ........................................................... Error! Bookmark not defined.303
        Questions .......................................................... Error! Bookmark not defined.304
    Section 2 Equilibrium ............................................... Error! Bookmark not defined.328
        Reversible reaction............................................ Error! Bookmark not defined.328
        Dynamic equilibrium .......................................... Error! Bookmark not defined.329
        Manufacture of ammonia ................................... Error! Bookmark not defined.332
        Sulphur .............................................................. Error! Bookmark not defined.333
        Hydroxides and nitrates ..................................... Error! Bookmark not defined.334
Unit 9 ORGANIC CHEMISTRY I .................................... Error! Bookmark not defined.360
    Section 1 Basic ideas about organic chemistry ....... Error! Bookmark not defined.360
        Some typical organic compounds and their structuresError!                                 Bookmark      not
        defined.360
        Homologous series............................................ Error! Bookmark not defined.361
        Isomerism .......................................................... Error! Bookmark not defined.361
        Questions .......................................................... Error! Bookmark not defined.363
    Section 2 Hydrocarbon ............................................ Error! Bookmark not defined.368
        Alkane – saturated hydrocarbon........................ Error! Bookmark not defined.368
        Alkene ............................................................... Error! Bookmark not defined.371
        Sources of hydrocarbons – crude oil ................. Error! Bookmark not defined.374
        Extension – naming halogenalkanes ................. Error! Bookmark not defined.375
        Questions .......................................................... Error! Bookmark not defined.376
Unit 10 ORGANIC CHEMISTRY II ................................. Error! Bookmark not defined.420
    Section 1 Alcohol and carboxylic acid ...................... Error! Bookmark not defined.420
        Alcohol .............................................................. Error! Bookmark not defined.420
        Carboxylic acid .................................................. Error! Bookmark not defined.421
        Questions .......................................................... Error! Bookmark not defined.422
    Section 2 Macromolecules....................................... Error! Bookmark not defined.429
        The main constituents of food – fats, proteins and carbohydratesError! Bookmark
        not defined.429
        Man-made fibres ............................................... Error! Bookmark not defined.433
        Differences between addition polymerisation and condensation polymerisation
         .......................................................................... Error! Bookmark not defined.435
        Questions .......................................................... Error! Bookmark not defined.435
For 2009 – 2010 examinations                                       Preparing for IGCSE chemistry

Preparing for IGCSE chemistry
Section 1 Naming inorganic compounds
Naming elements
     “元素”和“单质”的英文意思都是 “element”,有时为了区别,在强调“单质”时可用“free
element”。因此,单质和元素的英文名称是一样的,下面给出的既是元素的名称,同时又是
单质的名称。
1 主族元素和单质
ⅠA              ⅡA          ⅢA             ⅣA         ⅤA                 ⅥA          ⅦA         0
Hydrogen                                                                                        Helium
Lithium         Beryllium   Boron          Carbon     Nitrogen           Oxygen      Fluorine   Neon
Sodium          Magnesium Aluminium Silicon           Phosphorus Sulphur             Chlorine Argon
Potassium Calcium           Gallium        Gemanium Arsenic              Selenium Bromine Krypton
Rubidium        Strontium   Indium         Tin        Antimony           Tellurium   Iodine     Xenon
Caesium         Barium      Thallium       Lead       Bismuth            Polonium Astatine      Radon
Francium        Radium
2 过渡元素和单质
Fe: Iron       Mn: Manganese       Zn: Zinc Hg: Mercury      Ag:Silver
Au: Gold       Cu: Copper


Naming compounds
     化合物的命名顺序都是根据化学式从左到右读,这与中文读法顺序是相反的。表示原子
个数时使用前缀:
mono- di- tri- tetra- penta- hexa- hepta- octa- nona- deca-
  一        二     三    四        五       六          七   八        九          十
1 化合物正电荷部分的读法
     直呼其名,即读其元素名称
如:CO carbon monoxide                Al2O3 alminium oxide
     N2O4 dinitrogen tetroxide
     对于有变价的金属元素,更多的采用罗马数字来表示金属的氧化态。
如:FeO: iron(Ⅱ) oxide                  Fe2O3: iron(Ⅲ) oxide
     Cu2O: copper(Ⅰ) oxide            CuO: copper(Ⅱ) oxide
Tips: 非金属化合物用前缀表示原子个数,金属化合物不需要用前缀,只须用罗马数字标出就有多种价态
      的金属元素的化合价。
E.g. Naming the compounds below:

                                                  1
For 2009 – 2010 examinations                                           Preparing for IGCSE chemistry
MnO2 manganese(IV) oxide                         Cr2O3     chromium(III) oxide


FeCl3     iron(III) chloride                     CuS       copper(II) sulphide


SO3        sulphur trioxide                      N2O5          dinitrogen pentoxide


Fe2O3       iron(III) oxide                      FeO           iron(II) oxide
2.化合物负电荷部分的读法:
2.1 二元化合物
      常见的二元化合物有卤化物、氧化物、硫化物、氮化物、磷化物、碳化物、金属氢化物
等,命名是需要使用后缀-ide.
如:fluoride, chloride, bromide, iodide, oxide, sulphide, nitride, phosphide, carbide,hydride;
OH-的名称也使用后缀-ide hydroxide.
      非金属氢化物不用此后缀,而是将其看成其他二元化合物(见 2.2);非最低价的二元化
合物还要加前缀,如 O22-: peroxide                     O2-:superoxide
例如:NaF sodium fluoride               AlCl3 aluminium chloride        Mg2N3 magnesium nitride
        Ag2S silver sulphide
E.g. Naming the compounds below:
ZnS     zinc sulphide          ZnO        zinc oxide             ZnCl2     zinc chloride
NaH     sodium hydride         CO2    carbon dioxide              KOH      potassium hydroxide
CaF2 calcium fluoride          NaBr sodium bromide               Ca3P2 calcium phosphide
Na2O2 sodium peroxide          H2O2 hydrogen peroxide
2.2 非金属氢化物
      除了水和氨气使用俗称 water,ammonia 以外,其他的非金属氢化物都用系统命名,命
名规则根据化学式的写法不同而有所不同。对于卤族和氧族氢化物,H 在化学式中写在前面,
因此将其看成另一元素的二元化合物。
      例如:HF hydrogen fluoride               HCl hydrogen chloride
            H2S hydrogen sulphide
对于其他族的非金属氢化物,H 在化学式中写在后面,可以加后缀-ane,氮族还可加-ine
      例如: PH3 phosphine 或 phosphane                    B2H6 diborane
2.3 无氧酸
命名规则:hydro-词根-ic acid
例如:HCl hydrochloric acid              H2S      hydrosulphuric acid
E.g. Naming the compounds below:
HBr     hydrobromic acid             HI      hydroiodic acid
HF       hydrofluoric acid
                                                  2
For 2009 – 2010 examinations                                        Preparing for IGCSE chemistry
2.4 含氧酸
命名规则:中心原子词根(罗马数字表示化合价) - ic acid
例如:H2SO4 sulphuric(VI) acid
        H2SO3 sulphuric(IV) acid
Tips: 若中心原子的化合价没有表示出来,则默认该酸为其正酸或原酸。例如,sulphuric acid 就是指硫酸。
E.g. Naming the compounds below:
HClO4 chloric(VII) acid                                 HClO3 chloric(V) acid or chloric acid
H2SO3 sulphric(IV) acid                                 HClO     chloric(I) acid
HNO3      nitric(V) acid or nitric acid                 HNO2 nitric(III) acid
H3PO4 phosphoric(V) acid or phosphoric acid
2.5 盐
2.5.1 含氧酸根的命名
命名规则:在含氧酸的基础上去掉 -ic acid , 加上-ate
例如:SO42
              -
                  sulphate(VI) ion
        SO32-     sulphate(IV) ion
Tips: 若中心原子的化合价没有表示出来,则默认该酸根为其正酸根。例如,sulphate 就是指硫酸根, nitrate
     就是指硝酸根。
     而亚酸根也可以按以下规则来命名:
     在含氧酸的基础上去掉 -ic acid , 加上-ite。例如:
          -
     SO32     可以命名为:sulphite
2.5.2 正盐: 根据化学式从左往右分别读出阳离子和阴离子的名称
E.g. Naming the compounds below:
FeSO4 iron(II) sulphate(VI) or iron(II) sulphate        FeS         iron(II) sulphide
FeSO3 iron(II) sulphate(IV) or iron(II) sulphite         Na2CO3 sodium carbonate
KNO3      potassium nitrate(V) or potassium nitrate     KMnO4       potassium manganate(VII)
KNO2      potassium nitrate(III) or potassium nitrite    KClO       potassium chlorate(I)
KClO3 potassium chlorate(V) or potassium chlorate
2.5.3 酸式盐:同正盐的读法,酸根中的 H 读作 hydrogen。
例如 NaHCO3 sodium hydrogencarbonate
2.5.4 水合盐:结晶水读作 water 或 hydrate
例如: CuSO4 ·5H2O                copper(II) sulphate – 5 – water




                                                3
For 2009 – 2010 examinations                                     Unit 1 BONDING AND STRUCTURE

Unit 1 BONDING AND STRUCTURE
Section 1 States of matters
Learning objectives:
  (Please note: (S) denotes material in the Supplement (Extended syllabus) only)
1 Describe the states of matter and explain their interconversion in terms of the kinetic
  particle theory.
2 Describe and explain diffusion.
3 Describe evidence for the movement of particles in gases and liquids. A treatment of
  Brownian Motion is not required
4(s) Describe dependence of rate of diffusion on molecular mass (treated qualitatively)


Key words:
particle                 微粒                                  freezing        凝固
kinetic particle theory 分子运动理论                               melting         熔化
volume                  体积                                   evaporating     蒸发
vibrate                 振动                                   boiling         沸腾
motion                  运动                                   subliming       升华/凝华
condensing              液化                                   diffusion       扩散


Key ideas
Arrangement and movement of the particles in each of the three states
                         Solids                  Liquids                 Gases
 Shape           Have a fixed shape     Have no fixed shape      Have no fixed shape
 Volume          Have a definite volume Have a definite volume   Have no definite
                                                                 volume
 Density         Have a high density    Are usually lower dense Have a very low
                                        than solids              density
 Ability to flow Can not flow           Cannot flow quite easily Can flow very easily

 Ability     to Cannot be squashed               Can be slightly squashed Quite easy to be
 squashed                                                                 squashed
 Closeness of Closed one by one                  Have    a     little gap Far from each other
 particles                                       between two particles
 Diagrams    of
 arrangement




 Arrangement        Regular                      Irregular                     Irregular
                                                  4
For 2009 – 2010 examinations                                Unit 1 BONDING AND STRUCTURE
 Attractive        Very strong               Strong                   No force
 forces between
 particles
 Movement of       Vibrate       at   fixed Move around each other    Move freely
 particles         positions
 Examples          Iron                      Water                    Oxygen

Changes of state




Changes of state are linked to changes in the motion and arrangement of particles.

Diffusion
1 Definition: liquids or gases spread out in an available space.
              It’s an evidence for moving particles.
2 Factors influencing the speed of diffusion
1) Explanation by the kinetic particle theory
                           Speeds of particles moving

        The speed
        of diffusion
        depends on

                          Distance between particles




                                              5
For 2009 – 2010 examinations                                       Unit 1 BONDING AND STRUCTURE
2) Factors and explanations
   Factors            Effect                                     Explanations
                                            speeds      of    particles distance         between
                                            moving                      particles
State            Gases diffuse fastest      Particles in gases move Particles in gases are far
                                            fastest.                    from each other.
                 Liquids diffuse fast       In liquids particles move In liquids there are small
                 but more slower than       fast but more slower than gaps between these
                 gases                      in gases.                   particles.
                                            In solids these particles In solids these particles
            Solids can not diffuse          can only vibrate at fixed are close to each other.
            ( very slightly )               positions.
Temperature High       temperature          Particles move faster in Substances expand by
            favours high speed              high temperatures.          increasing temperatures.
            of diffusion                                                This       is    because
                                                                        distances        between
                                                                        particles become more
                                                                        large         in     high
                                                                        temperatures.
The relative The gas which has a            Particles in a gas with a
molecular    lower Mr diffuses              lower Mr moves faster.
masses of faster.
gases


Questions
Multiple Choice
There are forty questions on this paper. Answer all questions. For each question there are four possible
answers A, B, C and D.
1 When steam at 100oC condenses to water at 25oC, what happens to the water
  molecules?
  A They move faster and closer together.
  B They move faster and further apart.
  C They move slower and closer together.
  D They move slower and further apart.
2 A yellow precipitate is formed in the experiment shown




                                                   6
For 2009 – 2010 examinations                             Unit 1 BONDING AND STRUCTURE
  How is the precipitate formed?
  A Particles collide, diffuse and then react.
  B Particles collide, react and then diffuse.
  C Particles diffuse, collide and then react.
  D Particles diffuse, react and then collide
3 When there is no wind, the scent of flowers can be detected more easily on a warm
  evening than on a cold evening.
  This is because the molecules of the scent ……1…… ……2…… than in colder
  conditions. Which words correctly complete gaps 1 and 2?




4 At room temperature, in which substance are the particles furthest apart?
   A H2       B H2O        C Mg        D MgO
5 In which change of state do the particles become more widely separated?
   A gas to liquid
   B gas to solid
   C liquid to gas
   D liquid to solid
6 Some students are asked to describe differences between gases and liquids.
   Three of their suggestions are:
                      1 gas molecules are further apart;
                      2 gas molecules are smaller;
                      3 liquid molecules vibrate around fixed positions.
   Which suggestions are correct?
   A 1 only      B 2 only     C 3 only     D 1, 2 and 3
7 In which of the following are the particles arranged in a regular pattern?
   A a gas
   B a liquid
   C a metal
   D a solution
8 Heating a liquid causes it to become a vapour.
   What happens to the molecules of the liquid during this process?




                                           7
For 2009 – 2010 examinations                               Unit 1 BONDING AND STRUCTURE




9 A sealed conical flask contains a liquid and its vapour, as shown.




  What happens when a molecule in the vapour enters the liquid?




10 Oxides of nitrogen from car exhausts can spread through the atmosphere.




  This occurs because gas molecules move from a region of ……1…… concentration to a
  region of ……2…… concentration by a process called ……3…… .
  Which words correctly complete the gaps?



                                             8
For 2009 – 2010 examinations                                 Unit 1 BONDING AND STRUCTURE




11 Some sugar is dissolved in water.
  Which diagram shows how the particles are arranged in the solution?




12 The diagram shows how to obtain pure water from seawater.
  Where do water molecules lose energy?




13 Blue copper(II) sulphate crystals are soluble in water.




                                              9
For 2009 – 2010 examinations                               Unit 1 BONDING AND STRUCTURE




  What has happened after one week?
  A crystallisation
  B diffusion
  C distillation
  D filtration
14 A coloured liquid vaporises easily at room temperature. Some of the liquid is placed at
  the bottom of a sealed gas jar.
  Which diagram shows the appearance of the jar after several hours?




15 A shirt is stained with red ink from a pen.
  The shirt is left to soak in a bowl of water.
  Which process causes the red colour to spread?




  A diffusion
                                            10
For 2009 – 2010 examinations                                Unit 1 BONDING AND STRUCTURE
  B evaporation
  C melting
  D neutralisation
16 The melting points and boiling points of four substances are shown.
  Which substance is liquid at 100oC?




17 In which substance are the particles furthest apart at room temperature?
  A ethanol
  B methane
  C salt
  D sugar

Structured Questions
Core
1 A student placed a crystal of copper(II) sulphate in a beaker of water.
After one hour the crystal had completely disappeared and a dense blue colour was
observed in the water at the bottom of the beaker. After 48 hours the blue colour had
spread throughout the water.




(a) Use the kinetic particle theory to explain these observations.

________________________________________________________________________

________________________________________________________________________

______________________________________________________________________[2]
(b) Describe the arrangement and motion of the particles in the copper(II) sulphate crystal.

Arrangement____________________________________________________________

Motion________________________________________________________________ [2]
                                              11
For 2009 – 2010 examinations                                                                 Unit 1 BONDING AND STRUCTURE


2 The states of matter are solid, liquid and gas.
The diagram below shows how the molecules are arranged in these three states.




(a) State the name given to the change of state labelled

(i) A ...............................................................................................................................

(ii) B ...............................................................................................................................

(iii) C...............................................................................................................................
                                                                                                                                            [3]
(b) Which one of the following best describes the movement of molecules in the liquid
state?
Tick one box.


The molecules are not moving from place to place.


The molecules are sliding over each other.


The molecules are moving freely.
                                                                                                                                            [1]
(c) Which of the changes A, B or C, is endothermic?
Explain your answer.

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

.....................................................................................................................................[2]
(d) Choose from the following list of substances to answer the questions below.
                                                                 bromine
                                                                 chlorine
                                                                     iron
                                                                 mercury
                                                          sodium chloride
                                                                  sulphur
Name a substance which is

                                                                      12
For 2009 – 2010 examinations                                                                 Unit 1 BONDING AND STRUCTURE
(i) a gas at room temperature. ......................................................................................

(ii) a non-metallic liquid at room temperature. ...............................................................

(iii) a compound which is a solid at room temperature. ...................................................
                                                                                                                                           [3]
(e) A student set up the apparatus shown in the diagram below.




The white solid is formed because the molecules of hydrogen chloride gas and
ammonia gas move at random throughout the tube and eventually react with each other.
(i) State the name given to this random movement of molecules.

..................................................................................................................................
(ii) State the name of the white solid formed at X.

..................................................................................................................................
(iii) Suggest why the white solid is formed towards one end of the tube and not in the
middle.

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

...............................................................................................................................[3]
(f) What type of chemical reaction takes place when ammonia reacts with hydrochloric
acid?

.....................................................................................................................................[1]
(g) The diagram below shows a simple apparatus that can be used for measuring the
melting point of a solid.
The liquid in the beaker is heated slowly and the temperature at which the solid B melts
is recorded.




                                                                      13
For 2009 – 2010 examinations                                                                 Unit 1 BONDING AND STRUCTURE




(i) State the name of the piece of apparatus labelled A.

..................................................................................................................................
(ii) Solid B melted at 155oC.
Why would water not be a suitable liquid to put in the beaker when using this
apparatus to find the melting point of solid B?

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

..................................................................................................................................
(iii) Suggest why the liquid needs to be kept stirred.

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

...............................................................................................................................[3]

Extended
1Ethanoic acid is a colourless liquid at room temperature. It has the typical acid properties
and forms compounds called ethanoates.
(a) A pure sample of ethanoic acid is slowly heated from 0oC to 150oC and its temperature
is measured every minute. The results are represented on the graph below.




                                                                      14
For 2009 – 2010 examinations                               Unit 1 BONDING AND STRUCTURE




(i) Name the change that occurs in the region D to E.

______________________________________________________________________[1]
(ii) What would be the difference in the region B to C if an impure sample had been used?

______________________________________________________________________[1]
(iii) Sketch on the graph how the line would continue if the acid was heated to a higher
temperature.
                                                                                         [1]
(iv) Complete the following table that compares the separation and movement of the
molecules in regions C to D with those in E to F.




                                            15
For 2009 – 2010 examinations                              Unit 1 BONDING AND STRUCTURE




                                                                                   [5]
(b) Complete the word equations for the reactions of ethanoic acid.


           calcium + ethanoic acid         _____________________________

                                          +______________________________


          __________________+ ethanoic acid            zinc ethanoate + water      [2]
(c) Write the symbol equation for the reaction between ethanoic acid and sodium
hydroxide.

______________________________________________________________________[2]




                                            16
For 2009 – 2010 examinations                                    Unit 1 BONDING AND STRUCTURE

Section 2 Atomic structure
Learning objectives
1 State the relative charges and approximate relative masses of protons, neutrons and
  electrons.
2 Define proton number and nucleon number.
3 Use proton number and the simple structure of atoms to explain the basis of the Periodic
  table (see syllabus section 9), with special reference to the elements of proton number 1
  to 20.
4 Define isotopes.
5 State the two types of isotopes as being radioactive and non-radioactive.
6 State one medical and one industrial use of radioactive isotopes.
                                           235
7 Describe radioactive isotopes, such as     U as a source of energy.

8 Describe the build-up of electrons in ‘shells’ and understand the significance of the noble
  gas electronic structures and of valency electrons.


Key words:
proton                  质子                            isotopes             同位素
electron                电子                            radioactive         放射性的
neutron                 中子                            noble gas           稀有气体
nucleus                原子核                            valency electrons     价电子
Periodic Table       元素周期表


Key ideas:
Atomic structure

                 (protons and neutrons)




                                  Relative charge          Relative mass
                      Proton             +1                       1
                      Neutron             0                       1
                      Electron           -1                    1/1840
                                                 17
For 2009 – 2010 examinations                                    Unit 1 BONDING AND STRUCTURE
In an atom:
proton number (Z) = numbers of electrons
                  = numbers of protons

nucleon number (A) = proton number + neutron number
                   = Mr

Isotopes
1 Definition: atoms of the same element ( same proton number ) which have different
              numbers of neutrons
2 Examples
  1
   H 2H 3H                        35
                                    Cl 37
                                         Cl                235
                                                              U    238
                                                                      U
3 Uses of radioactive isotopes
                                                      235
1) power stations (as a source of energy , such as         U)
2) treat cancer

Electronic configurations
1 Shells
The electrons are found at considerable distances from the nucleus in a series of levels
called energy levels or shells. Each energy level can only hold a certain number of
electrons. Shells are numbered 1, 2, 3, 4, 5, 6, 7. These numbers are know as principal
quantum numbers (symbol n)
        quantum numbers (n)                 the number of electrons can be holded
             1                                              2
             2                                              8
             3                                              18
             4                                              32
But the outer shells can only hold 8 electrons at most.

2 Atomic structural diagrams
      18                                              35
           O                                               Cl




                                                     17P
                                                     18N
           8P
           10N




Tips: When you draw these diagrams, you should write out the proton number and neutron number
clearly. Because each element has several isotopes.

                                             18
For 2009 – 2010 examinations                                       Unit 1 BONDING AND STRUCTURE

Questions
Multiple Choice
There are forty questions on this paper. Answer all questions. For each question there are four possible
answers A, B, C and D.
1 What do the nuclei in hydrogen molecules contain?
  A electrons and neutrons
  B electrons and protons
  C neutrons only
  D protons only
2 Which particle is an ion?




3 Which number in the table is –1?




4 What is the electronic structure of an atom with a proton number 5 and a nucleon number
11?
  A 1, 8, 2       B 2, 8, 1       C 2, 3       D 3, 2
5 The nucleon number and proton number of the lithium atom are shown by the symbol

    . What is the correct symbol for the lithium ion in lithium chloride?



6 The table shows the numbers of particles present in the nuclei of four atoms or ions.




                                                  19
For 2009 – 2010 examinations                               Unit 1 BONDING AND STRUCTURE




Which two particles belong to the same element?
  A 1 and 2      B 1 and 4        C 2 and 3      D 2 and 4
7 What do the nuclei in hydrogen molecules contain?
  A electrons and neutrons
  B electrons and protons
  C neutrons only
  D protons only
8 What are the nucleon numbers for carbon and magnesium?




9 The proton numbers of four elements are shown.
  Which element forms a singly charged positive ion in its salts?




10 Hydrogen and helium have isotopes, as shown.
   In which of these isotopes does the nucleus have twice as many neutrons as protons?




                                            20
For 2009 – 2010 examinations                             Unit 1 BONDING AND STRUCTURE
11 Which atom has twice as many neutrons as protons?




12 An atom has the symbol
   Which value determines the position of the element in the Periodic Table?
   Ap
   Bq
   Cp–q
   Dp+q
13 Which row gives the outer electronic shell of fluorine and of neon?




14 Which diagram shows a positively charged ion?




                                           21
For 2009 – 2010 examinations                               Unit 1 BONDING AND STRUCTURE

15 Students are asked to draw a diagram of an atom with symbol
   Which diagram is correct?




16 The table describes the structures of four particles.




   What are the correct values of X, Y and Z?




17 The table shows the electronic structures of four elements.
   Which element is a noble gas?




                                              22
For 2009 – 2010 examinations                               Unit 1 BONDING AND STRUCTURE
18 Which formula represents a compound containing three atoms?
   A HNO3       B H2O       C LiF    D ZnSO4
19 The table shows the nucleon numbers and proton numbers of some atoms.




   How many are atoms of non-metallic elements?
   A1     B2     C3      D4
20 The diagrams show the nuclei of four different atoms.




   Which two atoms are isotopes of each other?
   A Q and R       B Q and T          C R and S     D S and T
21 Which statements about isotopic atoms of the same element are correct?




22 The diagrams show four particles.




  Which two diagrams show atoms that are isotopes of each other?
  A 1 and 2
  B 1 and 3
  C 2 and 3
  D 2 and 4
                                           23
For 2009 – 2010 examinations                             Unit 1 BONDING AND STRUCTURE

23 Two isotopes of helium are    and
  Which two diagrams show the arrangement of particles in these two isotopes?




24 Which number is different for isotopes of the same element?
  A number of electrons
  B number of full shells
  C number of nucleons
  D number of protons
25 Charcoal and uranium are used as sources of energy.
  Which of them are oxidised when used in this way?




                                           24
For 2009 – 2010 examinations                             Unit 1 BONDING AND STRUCTURE
26 Are hydrogen and uranium oxidised when used as a source of energy?




27 The elements H2 and 235U are both used as fuels.
  In these processes, the reactions are …..1….. and …..2….. oxidised.
  Which words correctly complete gaps 1 and 2?




28 The following elements have radioactive isotopes.
  Which element is used as a source of energy because of its radioactivity?
  A carbon
  B hydrogen
  C iodine
  D uranium
29 Five elements have proton numbers 10, 12, 14, 16 and 18.
  What are the proton numbers of the three elements that form oxides?
  A 10, 12 and 14
  B 10, 14 and 18
  C 12, 14 and 16
  D 14, 16 and 18
30 Which numbers are added to give the nucleon number of an ion?
  A number of electrons + number of neutrons
  B number of electrons + number of protons
  C number of electrons + number of protons + number of neutrons
  D number of protons + number of neutrons

Structured Questions
Core
1 Iron has several isotopes.
(i) What do you understand by the term isotopes?

______________________________________________________________________[1]
                                           25
For 2009 – 2010 examinations                               Unit 1 BONDING AND STRUCTURE
(ii) The table shows the number of subatomic particles in an atom of iron.




Complete the table to show the relative charge on each particle. [3]
(iii) State the number of nucleons in this isotope of iron.

______________________________________________________________________[1]
(e) Some isotopes are radioactive. State one industrial use of radioactive isotopes.

______________________________________________________________________[1]
(f) Iron reacts with very dilute nitric acid.


Write a word equation for this reaction.




                                                                                        [1]
Extended
1 (a) Complete the table which gives the names, symbols, relative masses and relative
charges of the three subatomic particles.




                                                                                        [3]
(b) Use the information in the table to explain the following.
(i) Atoms contain charged particles but they are electrically neutral because they
have no overall charge.

______________________________________________________________________

______________________________________________________________________[2]
(ii) Atoms can form positive ions.

                                             26
For 2009 – 2010 examinations                             Unit 1 BONDING AND STRUCTURE
______________________________________________________________________

______________________________________________________________________[2]
(iii) Atoms of the same element can have different masses.

______________________________________________________________________

______________________________________________________________________[2]
(iv) Scientists are certain that there are no undiscovered elements missing from the
Periodic Table from hydrogen to lawrencium.

______________________________________________________________________[1]

2 The table below gives the number of protons, neutrons and electrons in atoms or ions.




(a) Complete the table. The first line is given as an example. [6]
(b) Which atom in the table is an isotope of the atom which has the composition 11p, 11e
and 14n? Give a reason for your choice.

______________________________________________________________________

______________________________________________________________________[2]




                                           27
For 2009 – 2010 examinations                                  Unit 1 BONDING AND STRUCTURE

Section 3 Chemical bonding
Learning objectives
1 Describe the differences between elements, mixtures and compounds, and between
  metals and non-metals.
2 Describe alloys, such as brass, as a mixture of a metal with other elements.
3 Identify representations of alloys from diagrams of their structures.
4 Describe bond breaking as endothermic and bond forming as exothermic.
5 Describe the formation of ions by electrons loss or gain.
6 Describe the formation of ionic bonds between elements from Groups I and VII.
7 Describe the formation of ionic bonds between metallic and non-metallic elements.
8 Describe the lattice structure of ionic compounds as a regular arrangement of alternating
  positive and negative ions.
9 Describe the formation of single covalent bonds in H2, Cl2, H2O, CH4 and HCl as the
  sharing of pairs of electrons leading to the noble gas configuration.
10 Describe the electron arrangement in more complex covalent molecules such as N2,
   C2H4, CH3OH and CO2.
11 Describe the differences in volatility, solubility and electrical conductivity between ionic
   and covalent compounds.
12 Describe the giant covalent structures of graphite and diamond.
13 Relate their structures to the use of graphite as a lubricant and of diamond in cutting.
14 Describe the macromolecular structure of silicon(IV) oxide (silicon dioxide).
15 Describe the similarity in properties between diamond and silicon(IV) oxide , related to
   their structures.
16 Describe metallic bonding as a lattice of positive ions in a ‘sea of electrons’ and use this
   to describe the electrical conductivity and malleability of metals.


Key words
element       元素/单质                                lattice             晶格
mixture       混合物                                  chemical bonding   化学键
alloy         合金                                   ion                离子
delocalised   电离出的                                 anion              阴离子
ionic bond    离子键                                  sharing electrons   共用电子
cation        阳离子                                  tetrahedral    正四面体的
covalent bond 共价键                                  ductility      延性
compound          化合物                              malleability 展性
metallic bond     金属键                              lubricant      润滑剂/润滑的



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For 2009 – 2010 examinations                              Unit 1 BONDING AND STRUCTURE

Key ideas
Distingwish of substances
1 Relationship between all the kinds of substances in the world

                                                 metal
                 mixture

                                    element
 substance

                                                 non - metal
                 pure substance
                                                   ionic compound


                                    compound


                                                   covalent compound

2 Definitions of element , compound and mixture
1) Element – a substance which is made up of only one kind of atom.
i.e. O2 , 12C        , 14C ,     C60
Tips: ‘element’ 既有‘元素’的意思,又有‘单质’的意思。
2) Compound – substances which are formed when two or more elements chemically
combine together.
3) Mixture – contains more than one substance ( elements and / or compounds ).

Chemical bonding
Substances are made up of atoms , ions or molecules. There must be some forces
between these particles to hold them on.
The forces between these particles are called chemical bonds or chemical bonding.
There are four kinds of chemcal bonds in all the substances.




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For 2009 – 2010 examinations                                 Unit 1 BONDING AND STRUCTURE

                               Forces between atoms                       Covalent bonding




                               Forces      between anions and             Ionic bonding
                               cations


 CHEMICAL BONDING

                               Forces between cations and                 Metallic bonding
                               free electrons




                               Forces between molecules                   Intermolecular forces


Metallic bonds
1 Common properties of metals:
  good conductors of electricity
  good conductors of heat
  malleable and ductile
  shiny and silvery
Tips: malleable means that metals can be hammered into different shapes ( 展性 )
      ductile means that metals can be pulled out into thin wires        ( 延性 )

2 What is a metallic bond
Metallic bonding is a lattice of positive ions surrounded by mobile electrons
It is a force between positive ions and free electrons.


                                    Free electrons


                                   Metal ions

Metallic bonds are in Metals and alloys.

3 Properties and structures of metals
1) Why metals are malleable and ductile?
This is because of the ability of the atoms to roll over each other into new positions without
breaking the metallic bond.
2) Why metals are good conductors of electricity?
The delocalised electrons are free to move throughout the structure

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For 2009 – 2010 examinations                                   Unit 1 BONDING AND STRUCTURE




3) Why metals are good conductors of heat?
Heat energy is picked up by the electrons as additional kinetic energy (it makes them move
faster). The energy is transferred throughout the rest of the metal by the moving electrons.




4 Alloys
An alloy is a mixture of a metal with another element, usually another metal.




         free electron

                                                                         another element




                             typical structure of an alloy


Ionic bonds




                         +                                          -
                                   electrostatic forces

Some compounds are made up of cations and anions. There are electrostatic forces
between these ions. We call this kind forces ionic bonds.
Tips: A cation means the ion carrying positive charge. And an anion means the ion carrying negative
      charge.



                                                  31
For 2009 – 2010 examinations                                           Unit 1 BONDING AND STRUCTURE
1 Formation of ions
An atom is tend to form a noble gas electronic configuration. Because it is a very stable
structure. So atoms form the ions which have the same electronic configurations as noble
gases by losing or gaining electrons.
i.e.
A sodium atom has only one outer shell electron. So it is easy to lose this outer electron to
form a cation, which has the same structure as neon.




But a chlorine atom has seven outer shell electrons. It is easier to gain an electron to form
an anion, which has the same structure as argon.




Tips : How to determine the structure of an ion?
       The structure of an ion is basic on the number of the outer shell electrons of the atom. And the
       number of the outer shell electrons of an atom equals the Group number of this atom in the
       Periodic table. So that we can predict the structure of an ion by the position of this element
       in Periodic table.
                  Group I    Group      Group      Group       Group      Group      Group      Group
                             II         III        IV          V          VI         VII        0
      Number
      of    the      1          2          3          4           5          6          7         0
      outer
      shell
      electrons
      Formula     easy to    easy to    easy to    Difficult   easy to    easy to    easy to    Noble
      of   the    lose 1     lose 2     lose 3     to form     gain 3     lose 1     lose 1     gases
      ions        electron   electron   electron   ions        electron   electron   electron

                    M+         M2+        M3+                    M3-        M2-        M-
                                                    32
For 2009 – 2010 examinations                                       Unit 1 BONDING AND STRUCTURE
2 Ionic compound
The compounds which are made up of cations and anions are called Ionic compound.
1) ‘Dot’ and ‘cross’ diagrams of ionic compouns
i.e.
                                                                                                  2



             +                                                           2+


       Na                Cl                                        Mg                 O



                 NaCl                                                         MgO
   ● electron from chlorine atom                                   ● electron from oxygen atom
   × electron from sodium atom                                     × electron from magnesium atom

Alternatively, a simpler type of diagram can be used that only shows the valency
electrons.
                                                                                     2




                                                              2+
   +             Cl                                                      O
Na                                                       Mg



         NaCl                                                       MgO
Tips: Although both representations are correct, the simpler type of diagram shown above is preferred at
      IGCSE. And when you draw the diagram of an anion, you should not lost the relative charge of
      the anion.

2) Characters of ionic compound
Particles in the compound: Cations and anions. (Can not find small molecules in the
compound)




Forces between particles: Ionic bonding (electrostatic force)
Conduct electricity in its molten state and aqueous. But can not conduct electricity in its
solid state.
Have high melting/boiling points for the strong ionic bonds

3) How many compounds do belong to the ionic compound?

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For 2009 – 2010 examinations                                      Unit 1 BONDING AND STRUCTURE

   •   All the salts except AlCl3

   •   Metal oxides

   •   Hydroxides
4) Ionic lattice
The lattice structure in a crystal of an ionic compund, such as sodium chloride, is a regular
three – dimensional arrangement of alternating positive and negative ions. It is held
together by strong electrostatic forces ( ionic bonds). There is no molecules, just ions.




Covalent bonds
Some subtances are made up of atoms, such as HCl, but atoms carry no charge. So that
there must be something between the two atoms to hold them on. Actually these atoms are
connected by the sharing electrons.

                                      covalent bonding

                                      forces          forces

                                                  -              +
                               +
                               hydrogen
                                               sharing
                               nucleus                         chlorine
                                               electrons
                                                               nucleus

Covalent bonds are forces between sharing electrons and nucleus.
i.e. HCl molecule




                                                  Cl
                                          H

                                          sharing electrons


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For 2009 – 2010 examinations                                      Unit 1 BONDING AND STRUCTURE
1 ‘Dot’ and ‘cross’ diagrams of covalent compounds /structures




                Cl                                                          Cl             Cl
    H
                                           H        H

          HCl                                  H2                                  Cl2




                                    O               C           O



                                                 CO2

Tips: A covalent compound is the compound which only contains covalent bonds.
      Covalent compounds are made up of atoms. And these atoms are uncharged. Although atoms in a
      covalent compound carry positive or negative oxidation munbers , it does not mean these atoms
      carry positive or negative charge.
Zzzzz
zzzzzActually the oxidation number in a covalent compound stands for the position of the sharing pairs
      in this compound.
      For example in the HCl molecule , the sharing electrons is closer to the chlorine atom so that the
      chlorine atom has a negative oxidation munber , -1.
Most of time we use a line ‘ – ’ to stand for one pair of sharing electrons.
i.e.
                       H – Cl       H–O–H            Cl – Cl     O=C=O
This kind of fomula is called structural formula. It is more convenient to show the covalent
structures.

2 How many substances do belong to the covalent structures?
   •    Acids
   •    Non - metals
   •    Non – metal oxides
   •    Organic compounds
   •    All the other non – metal compounds
   •    AlCl3

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For 2009 – 2010 examinations                                   Unit 1 BONDING AND STRUCTURE
3 Covalent structures
                                                    Have small molecules in the
                                                    compound. Between molecules
               Simple molecular structure
                                                    there are very weak forces called
                                                    intermolecular forces.
 Covalent
 structures
                                                    Contains    many     hundreds    of
               Giant molecular structure            thousands of atoms joined by strong
                                                    covalent bonds

4 Properties of covalent compound
Be made up of molecules or atoms
Can not conduct electricity in any state.
As simple molecular substances, they are usually gases, liquids or solids with low melting
and boiling point.
As giant molecular substances, they are usually solids with very high melting and boiling
point, such as diamond , silicon and silicon(IV) oxide.

5 Diamond and graphite


                          Diamond                                   Graphite




 Diamond        This is made of a tetrahedron of carbon
 atoms. A carbon atom forms covalent bonds to four
 others. Each outer atom then bonds to three others
 and so on. Eventually thousands of carbon atoms are
 bonded together, in a giantcovalent structure.
 Properties
 1. It is very hard. This is because each atom is held
                                                                               strong
 in place by four covalent bonds. For the same
                                                                               covalent
 reason, it has a very high melting and boiling
                                                                               bonds
 point.
 2. It cannot conduct electricity, because there are
 no ions or free electrons to carry the charge.
 Uses        jewellery , drill bits and glass cutter

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For 2009 – 2010 examinations                                 Unit 1 BONDING AND STRUCTURE

 Graphite         This is made of flat sheets of carbon
 atoms. Each carbon atom forms covalent bonds to
 three others. This gives hexagonal rings of carbon
 atoms. These join to make flat sheets that lie on top
 of each other, held together by intermolecular forces.
 Properties
                                                                          strong
 1. It is soft and lubricant. This is because the sheets
                                                                          covalent
 of atoms can slide over each other easily.
                                                                          bonds
 2. It is a good conductor of electricity. This is because
 each atom has four outer electrons, but only forms
 three bonds. The fourth electron is free to move                            weak
 between the layers, carrying the charge.                                    intermolecular forces
 Uses          lubricant , electrode and pencil


6 Other giant covalent structures
1) Silicon
Silicon has the similar structure as diamond. A silicon atom forms covalent bonds to four
others. It forms a tetrahedral structure.




2) Silicon(IV) oxide
Silicon(IV) oxide also has the similar structure as diamond. Each silicon atom is connected
to other four oxygen atoms. And each oxygen atom connects to other two silicon atoms.
The ratio of silicon to oxygen is 1 to 2. So the formula of silicon(IV) oxide is SiO2. It not
means there is one silicon atom and two oxygen atoms in a silicon(IV) oxide molecules.
Because there is no silicon(IV) oxide molecule at all. Instead, silicon(IV) oxide is made
up of silicon and oxygen atoms.




                                                     37
                        For 2009 – 2010 examinations                          Unit 1 BONDING AND STRUCTURE

Summary

                                                        Particles in           Forces between                   Properties        and
          Types of structures
                                                        the structure          particles                        examples

                                                                                                                Have all the common
Metallic Structure                                     Metal     ions   and                                     properties of metals
                                                                                Metallic bonds
(metallic crystals)                                    free electrons                                           Metals and alloys


                                                                                                               High M.P./B.P. Hard
                                                                                                               Conduct electricity in molten state
Ionic Structure                                        Cations and anions       Ionic bonds
                                                                                                               and aqueous.
(ionic crystals)                                                                                               All the ionic compounds

                      Giant molecular structure/                                                               Very high M.P./B.P. Very hard
                                                             Atoms              Covalent bonds                 Do not conduct electricity in any
                      Macromolecular structure                                                                 states.
                            (atomic crystals)                                                                  diamond graphite SiO2 Si SIC
 Covalent

 Structure                                                                      Intermolecular                 Low M.P./B.P. Soft
                                                         Molecules
                                                                                                               Do not conduct electricity in any
                                                                                forces                         states.
                      Simple molecular structure         The molecules are      Covalent bonds exist ,in the   Most     of    the      covalent
                          (molecular crystals)           made up of atoms.      molecules, between atoms.      compounds & non - metals


                                                                  38
For 2009 – 2010 examinations                                       Unit 1 BONDING AND STRUCTURE

Questions
Multiple Choice
There are forty questions on this paper. Answer all questions. For each question there are four possible
answers A, B, C and D.
1 The diagram shows a molecule of hydrogen fluoride.




  In the molecule hydrogen fluoride, HF,
  A the hydrogen and fluorine share a pair of electrons.
  B the hydrogen and fluorine share a pair of protons.
  C the hydrogen gives the fluorine an electron.
  D the hydrogen gives fluorine a proton.
2 Carbon and chlorine form a chloride. What is the formula of this chloride?
  A CCl2 B CCl4 C CaCl2 D CaCl4
3 A new isotope of a divalent metal is discovered. Some students are asked to predict its
  properties. Which student’s predictions are correct?




4 The diagrams show two experiments to investigate metal reactivity.




  In which of these experiments could the metal be copper?
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For 2009 – 2010 examinations                               Unit 1 BONDING AND STRUCTURE




5 Which reaction is not a step in the production of iron from hematite in the Blast Furnace?
  A carbon (coke) burning in air to produce carbon dioxide
  B carbon monoxide being formed from carbon and carbon dioxide
  C iron oxide reacting with carbon monoxide to form iron
  D iron reacting with limestone to produce slag
6 Which item is sometimes made from stainless steel?




7 The chemical properties of an element depend mainly on the number of
  A electrons in the innermost shell.
  B electrons in the outermost shell.
  C fully occupied shells of electrons.
  D partly occupied shells of electrons.
8 The electronic structures of atoms P and Q are shown.




  P and Q react to form an ionic compound. What is the formula of this compound?
  A PQ2 B P2Q          C P2Q6     D P6Q2
9 What changes when an ion is made from an atom?
  A the number of electrons only
  B the number of neutrons only
  C the number of protons only
  D the number both of protons and of neutrons
10 Which change to an atom occurs when it forms a positive ion?
  A It gains an electron.
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For 2009 – 2010 examinations                            Unit 1 BONDING AND STRUCTURE
  B It gains a proton.
  C It loses an electron.
  D It loses a proton.
12 The electronic configuration of an ion is 2.8.8.
  What could this ion be?




13 How are the electrons arranged in a neon atom, Ne, and a sodium ion, Na +?




14 Which compound has ionic bonds?
  A hydrogen chloride
                                              41
For 2009 – 2010 examinations                              Unit 1 BONDING AND STRUCTURE
  B methane
  C sodium chloride
  D water
15 The table shows the electronic structures of four atoms.




  Which two atoms combine to form an ionic compound?
  A W and X     B W and Y      C X and Y       D X and Z
16 The diagram shows the outer shell electron arrangement of compound J that contains
  the elements Y and Z.




  What type of compound is J?
  A an alloy
  B a macromolecule
  C covalent
  D ionic
17 The diagram shows a model of a molecule containing carbon, hydrogen and oxygen.




  How many atoms of each element are in the molecule?




                                            42
For 2009 – 2010 examinations                              Unit 1 BONDING AND STRUCTURE




18 The table shows the electronic structures of four atoms.




  Which two atoms combine to form a covalent compound?
  A W and X       B W and Y       C X and Y   D X and Z
19 Butenedioic acid has the structure shown.




  What is the molecular formula of butenedioic acid?
  A CHO        B C4H4O4      C C6H4O2       D C6H4O6
20 Bottles of sodium hydroxide, sodium chloride and sugar have lost their labels.
  Students test a sample from each bottle. Their results are shown in the table.




  What are the correct labels for each bottle?

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For 2009 – 2010 examinations                            Unit 1 BONDING AND STRUCTURE




21 When it is used as a fuel, hydrogen combines with substance X.
  What is X?
  A carbon
  B methane
  C nitrogen
  D oxygen
22 A gas has the molecular formula NOCl.
  Which diagram could show molecules of the pure gas NOCl ?




23 The diagram shows the structure of methane.




                                          44
For 2009 – 2010 examinations                              Unit 1 BONDING AND STRUCTURE




  What is the total number of electrons used for bonding in this molecule?
  A2      B4      C8     D 10
24 The diagram shows the structure of hydrogen peroxide.

                                     H-O-O-H
  What is the total number of electrons used for bonding in this molecule?
  A3        B4        C6       D8
25 Which statement about gaseous hydrogen chloride and solid potassium chloride is
  correct?
  A Hydrogen chloride is covalent but potassium chloride is ionic.
  B Hydrogen chloride is ionic but potassium chloride is covalent.
  C They are both covalent compounds.
  D They are both ionic compounds.
26 The rows P, Q and R in the table show three pairs of structures.




  Which pair or pairs are isotopes?
  A P only    B P and Q only        C Q only        D Q and R only

                                            45
For 2009 – 2010 examinations                                Unit 1 BONDING AND STRUCTURE
27 In the diagrams, circles of different sizes represent atoms of different elements.
  Which diagram can represent hydrogen chloride gas?




28 The following statement is about chemical bonds.
  Covalent bonds are formed by the …1… of electrons. Covalent substances have …2…
  electrical conductivity.
  Which words complete the statement?




29 How many electrons are shared between the atoms in a molecule of methane, CH 4, and
  in a molecule of water, H2O?




30 In the molecules CH4, HCl and H2O, which atoms use all of their outer shell electrons in
  bonding?
  A C and Cl
  B C and H
  C Cl and H
  D H and O
31 Strontium, Sr, is a metal that forms an ionic chloride SrCl2.
  Sulphur, S, is a non-metal that forms a covalent chloride SCl2.
  Which compound is likely to have the higher melting point (m.p.) and which is more
  soluble in water?

                                             46
For 2009 – 2010 examinations                               Unit 1 BONDING AND STRUCTURE




32 Which of the following can be used as a lubricant?




33 In the circuit shown the bulb does not light.




  Which change would cause the bulb to light?
  A add more solid copper(II) sulphate to the beaker
  B add water to dissolve the copper(II) sulphate
  C replace the carbon electrodes with copper electrodes
  D reverse the connections to the electrodes
34 The diagram shows the structure of a substance.
  What is represented?




                                              47
For 2009 – 2010 examinations                                Unit 1 BONDING AND STRUCTURE




  A diamond
  B ethane
  C graphite
  D poly(ethene)
35 The ‘lead’ in a pencil is made of a mixture of graphite and clay.




  If the percentage of graphite is increased, the pencil slides across the paper more easily.
  Why is this?
  A Graphite conducts electricity.
  B Graphite is a form of carbon.
  C Graphite is a lubricant.
  D Graphite is a non-metal.
36 A student sets up the apparatus shown. The bulb does not light.




  After the student adds substance X to the water, the bulb lights.
                                             48
For 2009 – 2010 examinations                              Unit 1 BONDING AND STRUCTURE
  What could X be?
  A barium sulphate
  B carbon (or diamond)
  C copper (or graphite)
  D potassium sulphate
37 The diagram shows an electric circuit.




  For which two substances at X and Y does the bulb light up?




38 Which substance is a metal?




39 Which diagram best represents the structure of a solid alloy?




                                            49
For 2009 – 2010 examinations                              Unit 1 BONDING AND STRUCTURE
40The diagrams show the arrangement of electrons in three different atoms.




  Which atoms are metals?
  A 1 and 2 only    B 1 and 3 only     C 2 and 3 only     D 1, 2 and 3
41 Which property do all metals have?
  A They are hard.
  B They conduct electricity.
  C They form acidic oxides.
  D They react with water.
42 The diagram shows the properties of four substances.
  Which one could be magnesium?




43 The following statements are about alloys.
  • Alloys are …X…. .
  • …Y… alloys conduct electricity.
  Which words complete the statements?




                                           50
For 2009 – 2010 examinations                                 Unit 1 BONDING AND STRUCTURE
44 Which element is a solid non-metal?




45 Which two elements form an alloy when they are heated together?
  A chlorine and hydrogen
  B chlorine and zinc
  C copper and hydrogen
  D copper and zinc

Structured Questions
Core
1 Compounds and elements vary in their volatility, solubility in water and electrical Use
conductivity depending on their bonding.
(a) Place copper, methane and water in order of their volatility.




                                                                                            [1]
(b) Complete the table to show the solubility in water and electrical conductivity of various
solids.




                                                                                            [4]



                                              51
For 2009 – 2010 examinations                          Unit 1 BONDING AND STRUCTURE
2 Carbon exists in two forms, graphite and diamond.




Use ideas about structure and bonding to suggest
(i) why graphite is used as a lubricant,

______________________________________________________________________[1]
(ii) why diamond is very hard.

____________________________________________________________________[1]

3 The diagram shows models of various elements.




(a) Define the term element.

______________________________________________________________________[1]
(b) Which one of the models A to E represents a solid containing diatomic molecules?

______________________________________________________________________[1]
(c) Which two of the models A to E represent gases?

______________________________and____________________________________ [1]
                                           52
For 2009 – 2010 examinations                                Unit 1 BONDING AND STRUCTURE
(d) (i) Which one of the models A to E represents diamond?

______________________________________________________________________[1]
(ii) State the name of the element present in diamond.

______________________________________________________________________[1]
(iii) State a use of diamond other than in jewellery.

____________________________________________________________________[1]
(e) Structure E is a metal. State three physical properties which are characteristic of all
metals.

______________________________________________________________________

______________________________________________________________________

______________________________________________________________________[3]
(f) Metals are sometimes mixed with other elements in order to change their properties.
(i) What is the name given to a mixture of metals with other elements?

____________________________________________________________________[1]
(ii) Match up the metals in the boxes on the left with their uses on the right. The first
one has been done for you.




                                                                                              [4]
4 (a)Complete the following sentences using words from the list.

              chlorine     diamond             high       low         sharing
                    sodium     strong             transfer         weak
                                             53
For 2009 – 2010 examinations                              Unit 1 BONDING AND STRUCTURE


Covalent bonds are formed by the ____________of pairs of electrons. Simple covalent

molecules such as_________ and bromine have____________ melting points. Giant

covalent structures such as_____________ have many _______________bonds and have
high melting points.                                                              [5]
(b) The simplest covalent molecule is hydrogen.
    Draw a diagram to show how the electrons are arranged in a hydrogen molecule.




                                                                                       [1]

5 The diagram shows models of various structures,




(a) Which three of the structures A to F represent elements? Give a reason for your
answer.
structures________________________________________________________________

reason ________________________________________________________________[2]
(b) Which one of the structures A to F represents a gas containing single atoms?

______________________________________________________________________[1]
(c) (i) Which one of the structures A to F represents a gas containing diatomic molecules?

________________________________________________________________________
(ii) State the name of a gas which has diatomic molecules.

______________________________________________________________________[2]
(d) (i) Which one of the structures A to F represents graphite?
                                            54
For 2009 – 2010 examinations                                Unit 1 BONDING AND STRUCTURE


________________________________________________________________________
(ii) State one use of graphite.

______________________________________________________________________[2]
(e) Structure D represents a compound.
(i) State what is meant by the term compound.

______________________________________________________________________

______________________________________________________________________
(ii) Which one of the following substances is structure E most likely to represent?
Put a ring around the correct answer.

ammonia           hydrogen         chloride         methane         water            [2]
(f) Hydrogen chloride is a compound.
(i) Draw a diagram to show how the electrons are arranged in a molecule of hydrogen
chloride.
Show only the outer electrons.
                                                            show hydrogen electrons as ●
                                                             show chlorine electrons as x




                                                                                       [2]
(ii) State the name of the type of bonding present in hydrogen chloride.

______________________________________________________________________[1]
(iii) Hydrogen chloride dissolves in water to form an acidic solution (hydrochloric acid).
Describe how you would use litmus paper to show that this solution is acidic.

______________________________________________________________________

______________________________________________________________________[2]
(iv) Which one of the following values is most likely to represent the pH of a dilute
solution of hydrochloric acid?
Put a ring around the correct answer.

         pH 2         pH7           pH10             pH14                              [1]

(v) Complete the following equation for the reaction of hydrochloric acid with
                                             55
For 2009 – 2010 examinations                                Unit 1 BONDING AND STRUCTURE
magnesium.
                     Mg(s) + ________HCl (aq)         MgCl2(aq) + H2(g)                   [1]
(vi) Name the salt formed in this reaction.

______________________________________________________________________[1]

6 Look at the list of five elements below.
                                            argon
                                           bromine
                                           chlorine
                                            iodine
                                          potassium
(a) Put these five elements in order of increasing proton number.

______________________________________________________________________[1]
(b) Put these five elements in order of increasing relative atomic mass.

______________________________________________________________________[1]
(c) The orders of proton number and relative atomic mass for these five elements are
different. Which one of the following is the most likely explanation for this?
Tick one box.




(d) Which of the five elements in the list are in the same group of the Periodic Table?

______________________________________________________________________[1]
(e) (i) From the list, choose one element which has one electron in its outer shell.

______________________________________________________________________[1]
(ii) From the list, choose one element which has a full outer shell of electrons.

______________________________________________________________________[1]
(f) Which two of the following statements about argon are correct?
Tick two boxes.



                                             56
For 2009 – 2010 examinations                               Unit 1 BONDING AND STRUCTURE




(g) Potassium chloride can be made by reacting potassium with chlorine. The bonding in
potassium chloride is ionic.
What does this information tell you about
(i) the boiling point of potassium chloride,

______________________________________________________________________[1]
(ii) the electrical conductivity of molten potassium chloride?

______________________________________________________________________[1]
(h) Describe the change in the electronic structure of potassium and chlorine atoms when
they combine to make potassium chloride.
change in potassium atom

________________________________________________________________________
change in chlorine atom

______________________________________________________________________[2]

7 When rain water trickles through rocks, it dissolves some of the minerals present.
This water, which is bottled for drinking, is called mineral water.
The table shows the ions present in a litre of mineral water.




(a) What do you understand by the term ion?

______________________________________________________________________[1]
                                            57
For 2009 – 2010 examinations                                   Unit 1 BONDING AND STRUCTURE
(b) Which positive ion has the greatest concentration in this sample of water?

______________________________________________________________________[1]
(c) Complete the following equation to show how a calcium ion is formed from a calcium
atom.

                                  Ca → Ca2+       + _____ e-
                                                                                           [1]
(d) When this sample of mineral water is evaporated to dryness, various compounds
are formed. One of these compounds is calcium chloride.
Suggest the name of two other compounds which could be formed.

compound 1______________________________________________________________

compound 2___________________________________________________________ [2]
(e) Part of the structure of calcium chloride is shown below.




Use this diagram to work out the simplest formula for calcium chloride.

formula________________________                                                           [1]
(f) Complete the following table to show the electrical conductivity of calcium and calcium
chloride in the solid and liquid states.
Put a √ if the substance conducts.
Put a × if the substance does not conduct.




                                                                                           [2]
(g) A sample of water was contaminated with clay, which is insoluble in water.
Explain with the help of a labelled diagram, how you would separate the clay from
the water.
                                             58
For 2009 – 2010 examinations                              Unit 1 BONDING AND STRUCTURE




                                                                                    [3]

8 The diagram shows the structures of calcium chloride, calcium and chlorine.




        calcium chloride                   calcium                       chlorine
(a) Use ideas about structure and bonding to explain the following:
(i) Calcium chloride conducts electricity when molten but not when solid.

______________________________________________________________________

_____________________________________________________________________[2]
(ii) At room temperature, calcium is a solid but chlorine is a gas.

______________________________________________________________________

_____________________________________________________________________[2]
(b) Calcium is manufactured by the electrolysis of molten calcium chloride.




(i) State the products formed

at the anode, _____________________________________________________________
                                            59
For 2009 – 2010 examinations                                Unit 1 BONDING AND STRUCTURE


at the cathode. _________________________________________________________[2]
(ii) Suggest a non-metal that can be used as an anode in this electrolysis.

______________________________________________________________________[1]
(iii) A stream of inert gas is blown over the calcium as it is removed from the molten calcium
chloride. Suggest why a stream of inert gas is blown over the hot calcium.

______________________________________________________________________[1]
(iv) State the name of a gas which is inert.

______________________________________________________________________[1]
(c) Aqueous sodium hydroxide or aqueous ammonia can be used to test for calcium ions in
solution. Describe the results of these tests
with aqueous sodium hydroxide,

______________________________________________________________________[2]
with aqueous ammonia.

______________________________________________________________________[1]

Extended
1 Complete the following table.




                                             60
For 2009 – 2010 examinations                                Unit 1 BONDING AND STRUCTURE
2 Magnesium reacts with bromine to form magnesium bromide.
(a) Magnesium bromide is an ionic compound. Draw a diagram that shows the formula of
the compound, the charges on the ions and the arrangement of outer electrons around
the negative ion.
The electron distribution of a bromine atom is 2, 8, 18, 7.
                                    Use x to represent an electron from a magnesium atom.
                                    Use o to represent an electron from a bromine atom.




                                                                                          [3]
(b) In the lattice of magnesium bromide, the ratio of magnesium ions to bromide ions is
1:2.
(i) Explain the term lattice.

______________________________________________________________________

______________________________________________________________________[2]
(ii) Explain why the ratio of ions is 1:2.

______________________________________________________________________[1]
(iii) The reaction between magnesium and bromine is redox. Complete the sentences.

Magnesium is the_________________________ agent because it has________________

electrons.Bromine has been_______________ because it has____________electrons. [4]

3 The first three elements in Group IV are
                                          carbon,
                                          silicon,
                                        germanium.

(a) The element germanium has a diamond-type structure. Describe the structure of
germanium. A diagram is acceptable.




                                                                                          [2]
(b) Unlike diamond, graphite is soft and is a good conductor of electricity.
(i) Explain why graphite has these properties.

______________________________________________________________________

______________________________________________________________________
                                              61
For 2009 – 2010 examinations                                Unit 1 BONDING AND STRUCTURE


______________________________________________________________________[3]
(ii) Give a use of graphite that depends on one of these properties.

property_________________________________________________________________

use__________________________________________________________________ [1]
(c) Carbon dioxide and silicon(IV) oxide have similar formulae but different types of
structure.

(i) Give the formulae of these oxides.

______________________________________________________________________[1]
(ii) How are their structures different?

______________________________________________________________________

______________________________________________________________________[2]
(d) All these elements form compounds with hydrogen called hydrides. The saturated
hydrides of carbon are the alkanes. Predict the formula of the hydride of germanium
which contains two germanium atoms.

______________________________________________________________________[1]

4 The table shows the melting points, boiling points and electrical properties of the six
substances A to F.




(i) Which three substances are solids at room temperature?

______________________________________________________________________[1]
(ii) Which one is an ionic compound?

______________________________________________________________________[1]
                                              62
For 2009 – 2010 examinations                               Unit 1 BONDING AND STRUCTURE
(iii) Which one is a gas at room temperature?

______________________________________________________________________[1]
(iv) Which two substances are liquids at room temperature?

______________________________________________________________________[1]
(v) Which substance is a metal?

______________________________________________________________________[1]
(vi) Which one is an impure substance?

______________________________________________________________________[1]

5 (a) The structure of a typical ionic compound is a regular arrangement of positive and
negative ions.




(i) What is the name of this regular arrangement of particles?

______________________________________________________________________[1]
(ii) Give two physical properties of ionic compounds.

______________________________________________________________________

______________________________________________________________________[2]
(b) Ions are formed by electron loss or gain. The electron distribution of a magnesium
atom is 2 + 8 + 2 and of a nitrogen atom is 2 + 5.
(i) Give the formula of the magnesium ion.

______________________________________________________________________[1]
(ii) Give the formula of the nitride ion.

______________________________________________________________________[1]
(iii) What is the formula of the ionic compound, magnesium nitride?

______________________________________________________________________[1]
(iv) In this compound there is an ionic bond. Why are the two ions attracted to each other?

______________________________________________________________________[1]

                                             63
For 2009 – 2010 examinations                                    Unit 1 BONDING AND STRUCTURE
6 It was reported from America that a turbine engine, the size of a button, might replace
batteries. The engine would be built from silicon which has suitable properties for this
purpose.
(a) (i) Why are batteries a convenient source of energy?

______________________________________________________________________[1]
(ii) The engine will run on a small pack of jet fuel. What other chemical is needed to burn
this fuel?

______________________________________________________________________[1]
(b) Silicon has the same type of macromolecular structure as diamond.
(i) Explain why one atom of either element can form four covalent bonds.

______________________________________________________________________

______________________________________________________________________[2]
(ii) Predict two physical properties of silicon.

______________________________________________________________________

______________________________________________________________________[2]
(iii) Name a different element that has a similar structure and properties to silicon.

______________________________________________________________________[1]
(c) Silicon is made by the carbon reduction of the macromolecular compound, silicon(IV)
oxide.
(i) Balance the equation for the reduction of silicon(IV) oxide.


                                                                                            [1]
(ii) Explain why the silicon(IV) oxide is said to be reduced.

______________________________________________________________________[1]
(iii) Describe the structure of silicon(IV) oxide. You may use a diagram.




____________________________________________________________________[2]

7 Strontium and sulphur chlorides both have a formula of the type XCl 2 but they have
different properties.




                                              64
For 2009 – 2010 examinations                                 Unit 1 BONDING AND STRUCTURE




(a) The formulae of the chlorides are similar because both elements have a valency of 2.
Explain why Group II and Group VI elements both have a valency of 2.

______________________________________________________________________

______________________________________________________________________[2]
(b) Draw a diagram showing the arrangement of the valency electrons in one covalent
molecule of sulphur chloride.
Use x to represent an electron from a sulphur atom.
Use o to represent an electron from a chlorine atom.




                                                                                         [3]
(c) Explain the difference in electrical conductivity between the following.
(i) solid and liquid strontium chloride

______________________________________________________________________[1]
(ii) liquid strontium chloride and liquid sulphur chloride

____________________________________________________________________[1]

8 There are three types of giant structure – ionic, metallic and macromolecular.
(a) Sodium nitride is an ionic compound. Draw a diagram that shows the formula of the
compound, the charges on the ions and the arrangement of the valency electrons around
the negative ion.

                                         Use x to represent an electron from a sodium atom.
                                        Use o to represent an electron from a nitrogen atom.




                                                                                         [3]
                                              65
For 2009 – 2010 examinations                      Unit 1 BONDING AND STRUCTURE
(b) (i) Describe metallic bonding.
________________________________________________________________________

______________________________________________________________________[3]
(ii) Use the above ideas to explain why
metals are good conductors of electricity,

______________________________________________________________________[1]
metals are malleable.

______________________________________________________________________[2]
(c) Silicon(IV) oxide has a macromolecular structure.
(i) Describe the structure of silicon(IV) oxide (a diagram is not acceptable).

_______________________________________________________________________

_______________________________________________________________________

______________________________________________________________________[3]
(ii) Diamond has a similar structure and consequently similar properties.
Give two physical properties common to both diamond and silicon(IV) oxide.

____________________________________________________________________

____________________________________________________________________[2]




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