Question

The preference of three unpaired electrons in the ground state of phosphorous can be explained by:

• A. Pauli's exclusion principle
• B. Aufbau principle
• C. Heisenberg's uncertainty principle
• D. Hund's rule

Answer 1

The correct option is D Hund's rule

According to Hund's rule of maximum multiplicity, electron pairing does not occur until each degenerate orbital has one electron each.
In Phosphorus, atomic number = 15
So. electronic configuration = $1s^{2}2s^{2}2p^{6}3s^{2}3p_x^{1}3p_y^{1}3p_z^1$