Electron Pairing Rules
Pauli Exclusion Principle (Mac's)
In an atom or molecule, no two electrons can have the same four electronic quantum numbers. As an orbital can contain a maximum of only two electrons, the two electrons must have opposing spins.
Pauli Exclusion Principle
states that a maximum of two electrons can occupy a single atomic orbital but only if the electrons have opposite spins
Aufbau Principle
states that each electron occupies the lowest energy orbital available
Hund's Rule
states that single electrons with the same spin must occupy each equal-energy orbital before additional electrons with opposite spins can occupy the same orbitals
Aufbau Principle (Mac's)
Electrons will occupy the lowest E position available.
Hund's Rule (Mac's)
Every orbital in the same sublevel is singly occupied before any orbital is doubly occupied. All of the electrons in a singly occupied orbital have the same spin.