1. Notes #5: History of the Atom (pt 5) - Orbitals!
WCHS Chemistry
**NEED YOUR PERIODIC TABLES!**

2. ELECTRON ORBITALS
What Bohr didn’t figure out was that each region of his “orbits” was broken down into smaller regions → ORBITALS!
However, Bohr was correct on:
Low energy closest to the nucleus
High energy the farther out you go

3. Orbitals # of varieties Pictures
ORBITAL SHAPES
Orbitals
# of varieties
Pictures
DON’T NEED TO KNOW! S 1 p 3 d 5 f 7

4. S & p orbitals animation Scandium
Energy Level
# of sublevels
Orbital Types
# of Orbitals
Max # of e-s 1 1
s(1) 1 2 2 2
s(1)p(3) 4 8 3 3
s(1)p(3)d(5) 9 18 4 4
s(1)p(3)d(5)f(7) 16 32
S & p orbitals animation
Scandium

5. WE NEED A NEW MODEL Aufbau Principle
Start at the lowest energy level and fill up from there. (lazy electrons)
NOTICE 4s!!!
Hund’s Rule
Fill each orbital before doubling up. (electrons don’t share)

6. Rules for Writing e- Configuration: Big # = Energy Level
When filling orbital:
One e- in each before doubling up
Double up before moving up!
Rules for Writing e- Configuration:
Big # = Energy Level
Little # = # of electrons in that sublevel

7. AUFBAU’S PRINCIPLE
= Start at lowest energy level and fill up from there
CAN YOU THINK OF A SITUATION THAT VIOLATES THIS PRINCIPLE?
Excited State!