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Atomic-Structure Powered By Docstoc
					Atomic Structure

Lesson Objectives:
1. To know what is atomic structure.
2. To be able to draw the structure of atoms of
   the first 20 elements in the periodic table.
       Look at the size of THAT!!
                           Measurements in metres
•   Distance to the sun          100,000,000,000
•   Height of Mt Everest                   10,000
•   Human                                      1.5
•   Grain of sand                          0.0001
•   Sugar molecule                  0.000000001
          How small?!?!??
• If you pretended a whole atom was the
  size the new Wembley Stadium, its
  nucleus would be the size of a pea in the
  middle of the pitch.
Let’s Model!!
   What’s in an atom anyway?
  There are 3 different particles within an

• Protons – with a charge of +1 and a mass of 1
• Neutrons – with no charge and a mass of 1
• Electrons – with a charge of -1 and a mass of
  1/2000 (i.e. almost 0)
     Where might one find these
• In the nucleus we find
  neutrons and protons
  (the big heavies).
• The overall charge of
  the NUCLEUS is +
• Whizzing around the
  nucleus are electrons
  (the little guys).
     What keeps it all together?
• The nucleus in an atom is positively charged
• Opposite charges attract each other so the
  positive nucleus attracts the negative
  electrons                    -ve electrons

          -ve electrons
                                   +ve nucleus

                          -ve electrons
  Do the electrons just fly around at
• Electrons are arranged in different shells around the nucleus.
• The innermost shell is filled first and then the rest until each is filled.
• There is a fixed number of electrons that each shell can hold.

           shell      maximum number of electrons
           first      2
           second     8
           third      8
           fourth     18
Electron configuration
Do I know what is atomic structure?
• Complete the worksheet.
            Atomic number
• Atoms are neutral (i.e. they have no
• So this means…………..
     number of protons = number of electrons
• We call the number of protons an element
  has the ATOMIC NUMBER (a.k.a. the
             Mass number
• Remember!!!!
  – Protons have a mass of 1.
  – Neutrons have a mass of 1.
  – Electrons have a mass of 0 (almost).
       So, every element….
• …has its own atomic number and it’s own
  mass number.
 Can I use this knowledge to draw
       atoms of an element?
• Draw the atomic structure of the following
  elements (remember to use the atomic number
  and mass number to work out the particles in an
  – Lithium (atomic number: 3; atomic mass: 7)
  – Carbon (atomic number: 6; atomic mass: 12)
  – Chlorine (atomic number: 17; atomic mass: 35)
• Complete the quiz at:
          The Atom Song

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