1. Electron configuration explained.......

2. Energy levels within an atom....
Shell number
Total number of electrons
(2n2)
Number of subshells
Subshell in shell
Number of orbitals in subshell 1 2 1s 8 2s 2p 3 18 3s 3p 3d 5 4 32 4s 4p 4d 4f 7 50
5s etc etc
1 etc etc

3. Subshell energy levels

4. How do the sub shells fill up?
2s 2p
3s 3p 3d
4s 4p 4d 4f
5s 5p 5d 5f
6s 6p 6d 6f etc
7s 7p 7d 7f etc

5. Orbital shapes
d orbitals
s orbital
p orbitals

6. Why is all this sooooooo important?
Outer most electrons are called the:
VALENCE ELECTRONS
Valence e- are involved in chemical reactions!!!
By knowing the configuration, we can attempt to predict the chemical nature of an element

7. Why is all this sooooooo important?
We have been describing “ground state” for e- configuration or the most stable state.
If 1 or more e- occupies a higher energy subshell out of order, then the atom is in an:
“EXCITED STATE”