Question

Explain Hund's rule with an example.

Answer 1

1. Hund’s rules sets principles for pairing of electrons in p, d and f orbitals.
2. The rule states that every orbital in a sub-shell is singly occupied or contain one electron before pairing of electrons in any one orbital. Also electrons of same spin exists in all singly occupied orbitals.

Example

1. Boron, Carbon, Nitrogen and Oxygen have one, two, three and four electrons in the p orbital respectively.
2. The pairing of electron in sub-shells of these elements with respect to Hund’s rule is given as,