Electron Distribution
• Goal: Determine electron structures in
atoms
• Orbital level
• Sublevel
How are these organized?
N=1
N=2
N=3
N=4
s
p
s
s
p
Level 1 sublevels
s
p
Level 2 sublevels
Level 3 sublevels
d
d
f
Level 4 sublevels
Remember: 1s is smaller than 2s,
2s is smaller than 3s, etc.
How about energy?
Which has the most?
How do atoms put their electrons
in these sublevels?
• Lowest energy levels are filled first.
• Sublevels are filled “s”, then “p”, then “d”,
then “f”.
• Well, sort of...
Orbitals
p
d
s
1
Principal quantum number
2
1s
2s
2p
3
3s
3p 3d
4
4s
4p 4d
4f
5
5s
5p
5d
5f
6
6s
6p
6d
6f
7
7s 7p
7d
7f
f
1s orbital holds two electrons
ee-
Then consider the next orbital: 2s (which also holds only two e-.)
e-
e-
e- e-
Electron configuration for …
Scandium
• Look up the number of electrons (same as
the number of protons).
• Use the diagonal rule.
26
21
• Scandium is #21. That means Sc has _____
electrons.
Electron configuration for …
Scandium
2
2
6
2
6
2
1s 2s 2 p 3s 3 p 4s 3d
1
Energy level (Principle Quantum #)
Sublevel
1s
2
# of electrons
(add these)
Electron configuration for …
Scandium
Add These
2
2
6
2
6
2
1s 2s 2 p 3s 3 p 4s 3d
1
Practice
Electron configurations for:
• Neon 1s 2s 2 p
• Aluminum 1s 2 2s 2 2 p 6 3s 2 3 p1
• Vanadium
1s 2 2s 2 2 p 6 3s 2 3 p 6 4s 2 3d 3
2
2
6
2
2
6
2
1
1s 2s 2 p 3s 3 p