# Hund rulesZoomA-Z

## Subject - General Chemistry

Hund's rules developed in 1927 by Friedrich Hund determine the energetic sequence of term symbols associated with a certain electron configuration of an atom:

1. In term symbols derived from equivalent electrons, the term with the highest spin multiplicity shows the lowest energy.
2. If several term symbol meet this criterion, the one with the highest orbital degeneration (maximum $L$) shows the lowest energy.
3. The energy of the lowest levels increases with $J$ values if the values are derived from a less than half occupied orbital, otherwise it decreases.