What is the Hound's rule in chemistry?
It is the rule for filling of electrons in orbitals. It states
that,
When orbitals of equal energy (such as px, py, pz) are available
electrons, they fill orbitals singly to keep the spin parallel.
For example,
N(Z=7)= 1s2, 2s2, 2px2, 2py1 (wrong)
N(Z=7)= 1s2, 2s2, 2px1, 2py1, 2pz1 (correct)