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
• 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.
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
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
Do I know what is atomic structure?
• Complete the worksheet.
• 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
– 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
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