electrons fill the orbitals one at a time, starting with the lowest energy orbital then proceeding to the one with higher energy.
Aufbau Principle
single electrons with the same spin must occupy each equal- energy orbital before additional electrons with opposite spins can occupy the same orbitals.
hunds rule
state that only two electrons occupy an orbital, and they must have opposite spins
Pauli Exclusion Principle
-a probability that the electron can be found in a certain volume in space around the nucleus -this volume or region of space around the nucleus