1. Electron Distribution
Goal: Determine electron structures in atoms
Orbital level
Sublevel

2. How are these organized?
Level 1 sublevels
N = 1 s p
Level 2 sublevels
N = 2 s
N = 3
Level 3 sublevels s p d
N = 4
Level 4 sublevels s p d f

3. Remember: 1s is smaller than 2s, 2s is smaller than 3s, etc.
How about energy?
Which has the most?

4. 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...

5. Diagonal Rule Orbitals Principal quantum number 3s 3p 3d 4s 4p 4d 4f1 2 3 4 5 6 7
Diagonal Rule

6. 1s orbital holds two electrons

7. Then consider the next orbital: 2s (which also holds only two e-.)

8. Electron configuration for … Scandium
Look up the number of electrons (same as the number of protons).
Use the diagonal rule.
Scandium is #21. That means Sc has _____ electrons. 26 21

9. Electron configuration for … Scandium

10. Energy level (Principle Quantum #)
Sublevel
# of electrons
(add these)

11. Electron configuration for … Scandium
Add These

12. Practice Electron configurations for:
Neon
Aluminum
Vanadium