1. Electron Arrangement

2. Orbital Diagrams
Electrons want to be in the most stable configuration possible.
The ways in which electrons are arranged in orbitals is called their orbital diagram
An orbital diagram tells us in which orbitals electrons for an element are located

3. Aufbau Principle
The aufbau principle states that electrons will always occupy the orbitals of lowest energy first.
Each box represents an atomic orbital

5. Pauli Exclusion Principle
An atomic orbital may describe at most, two electrons.
For two electrons to occupy the same orbital, they must have opposite spins
To indicate spin, use

6. Hund’s Rule
Electrons occupy orbitals of the same energy in a way that makes the number of electrons with the same spin as large as possible.

7. Examples