1. Hog Hilton Rules
Hogs are lazy. (They don’t like to climb stairs if they don’t have to.)
Hogs can’t stand each other each other except when rule #1 forces them to be together.
If hogs are in the same room they will face in opposite directions.
They stink so you can’t put more than 2 hogs in the same room.

2. Electron Configuration Rules
Electrons are lazy. (Aufbau Principle)
Electrons don’t like to be together unless they have to. (Hund’s Rule)
If electrons are in the same orbital, they spin in opposite directions. (Pauli Exclusion Principle)
Only 2 electrons can fit in each orbital. (Pauli Exclusion Principle)

3. Electron Configuration…
General format:
n l e n = quantum number (energy level)
l = subshell (sublevel) letter
e- = number of electrons
Fill the lowest energy levels first.
in this order: 1s 2s 2p 3s 3p 4s 3d 4p
No more than 2 electrons per orbital.
reminders:
s = 1 orbital
p = 3 orbitals
d = 5 orbitals
f = 7 orbitals
 2e-
 6e-
 10e-
 14e-

4. examples: H: 1s1 He: 1s2 Li: 1s2 2s1 Co: 1s2 2s2 2p6 3s2 3p6 4s2 3d7
Add up all the electron #s and it should equal the total number of electrons in the element.

5. Condensed Electron Configuration
distinguishes the inner electrons from the valence electrons.
Valence electrons are the outer most electrons and are involved in chemical reactions.
Examples:
Li:
[He] 2s1
Co:
[Ar] 4s2 3d7
BIG HINT: The condensed electron configuration is on your Periodic Table