Electron configuration
Electrons in atoms





Electrons orbit the nucleus in energy levels called shells.
Electrons occupy the lowest energy level first.
The lowest energy level is nearest the nucleus.
The first energy level can only hold 2 electrons.
The next energy levels each hold 8 electrons.
If we take oxygen, with an atomic number of 8, we can represent the arrangement of its 8
electrons like this:
oxygen 2,6
Activity 1
Tracking the electrons
In the boxes below, draw atomic diagrams for the named elements. You will need to look at a
periodic table to find their symbols as well as their atomic numbers.
1. helium
2. carbon
3. sulfur
4. magnesium
5. aluminium
6. argon
© www.teachitscience.co.uk 2012
19411
Page 1 of 3
Electron configuration
Activity 2 Using the clues!
1.
2.
3.
4.
Identify the elements below.
Write the symbol of each one in its middle circle.
Below each diagram, write the element name and how the electrons are arranged.
The first one has been done for you.
1.
2.
3.
5.
6.
nitrogen 2,5
4.
Activity 3 Looking for patterns
Use a periodic table to help you complete the charts.
group
1
symbol
atomic
number
electron
configuration
group
0
lithium
helium
sodium
neon
potassium
argon
symbol
atomic
number
electron
configuration
Questions
1. What patterns do you notice between the members of Group 1?
2. What patterns do you notice between the members of Group 0?
3. What patterns would you expect to see as you go down Group 2?
© www.teachitscience.co.uk 2012
19411
Page 2 of 3
Electron configuration
Answers
Activity 1 Tracking the electrons!
Answers should show evidence of the following:
1.
2.
3.
4.
5.
6.
He helium 2 (atomic no: 2)
C carbon 2,4 (atomic no: 6)
S sulfur 2,8,6 (atomic no:16)
Mg magnesium 2,8,2 (atomic no: 12)
Al aluminium 2,8,3 (atomic no: 13)
Ar argon 2,8,8 (atomic no: 18)
Activity 2 Using the clues!
1. N nitrogen 2,5
2. P phosphorus 2,8,5
3. B boron 2,3
4. Cl chlorine 2,8,7
5. Ne neon 2,8
6. Ca calcium 2,8,8,2
Activity 3 Looking for patterns
Group
1
Symbol
Atomic
number
Electron
configuration
Group
0
Symbol
Atomic
number
Electron
configuration
lithium
Li
3
2,1
helium
He
2
2
sodium
Na
11
2,8,1
neon
Ne
10
2,8
potassiu
m
K
19
2,8,8,1
argon
Ar
18
2,8,8
Answers:
1.
2.
3.
As you go down the table the next element has 8 more electrons. Each outer shell has 1
electron.
As you go down the table the next element has 8 more electrons. Each outer shell is full.
As you go down the table the next element has 8 more electrons. Each outer shell has 2
electrons.
© www.teachitscience.co.uk 2012
19411
Page 3 of 3