I need help. In simple english please, what is Hund's Rule, Pauli Exclusion Principal, and the Aufbau Principal? I need to know these. Please try to be simple as possible because I'm not understanding right now, haha.

Question

Thanks!! :)

Answer 1

Hund's rule: Electrons will occupy single orbits in different orbitals before any orbital has a pair of electrons.
ie: if you have three electrons to put in to three empty p orbitals, then one electron will go into each orbital, in no case will two go into one orbital before each orbital has at least one eletctron.
Pauli Exclusion: No electron can have the same set of quantum numbers, ie, no two electrons can occupy the same exact energy state in an atom.
Aufbau: This is a principle that says if an atom has empty electron positions, the and you start filling the available energy levels, each electron will go into the lowest energy level then currently available (remember pauli on this).