Question

If hund's rule is invalide then magnetic moment of phosphorus (15) will be:

Answer 1

Hund rule states that no electron can pair without filling empty orbitals and if it is voilated than phosphorus will have 2 electron in its 3s orbital 2 electron in 3px and 1 in 3py so only one electron is unpaired and hence magnetic moment will be √(1)(1+2)=√3.