Pauli Exclusion Principle.

Pauli Exclusion Principle.

1. Two electrons in an atom can't have identical quantum numbers.

2. The Pauli exclusion principle is part of one of our most basic observations of nature:

   • particles of half-integer spin must have antisymmetric wavefunctions
   • particles of integer spin must have symmetric wavefunctions.

3. In one orbital a maximum of two electrons can be found and the two electrons must have opposing spins.

   • One would spin up ( +1/2) and the other would spin down (-1/2).