Bell Work
1. PRE-AP ONLY: Draw an Aufbau Chart.
2. Write the Electron Configuration for
1.
2.
3.
4.
H
LI
P
Fe
3. What does the Aufbau Principle say?
What You Should Know How to Do
1. Aufbau Chart:
1. Pre-AP Draw & Read
2. Chem I Read
2. Write Electron Configurations
3. State Aufbau Principle
Spherical Radii of the Orbitals
Pauli Exclusion Principle
• Electrons are subject to the Pauli Exclusion
Principle, so:
No electron can occupy the same quantum
state as another
• So, how do 2 electrons occupy the same
energy level and orbital?
Pauli Exclusion Principle
• They have “spin”
• electrons in the same orbital will have
different “spins”
– An analogy is to think of it as clockwise and
counterclockwise spinning
• These spins are called “up” spin and “down”
spin
– They are written as
Hund’s Rule
• Each sub-orbital will have 1 electron before
any get a second
• Two ways to think of it
1. The Candy Rule – it’s not fair if some get 2 pieces
of candy and some get none, first everyone gets
a piece, then we start handing out a second
piece
2. The Urinal Rule
Hund’s Rule
• Two ways to think of it
1. The Candy Rule – it’s not fair if some get 2 pieces
of candy and some get none, first everyone gets
a piece, then we start handing out a second
piece
2. The Urinal Rule (for the guys) – no “pairing” until
you have to
Which is Correct?
Class Work
1. Show Hund’s Rule for:
1.
2.
3.
4.
H
He
C
F
2. Write the electron configuration for H, N, Na,
Cl, K, V, Cu, Se, Kr, Y
Exit Ticket
• Draw Hund’s Rule for:
– Li
– Ne
• Write the electron configuration for:
–B
– Al
– Ga