Amongst the following elements whose
electronic configuration are given below, the
one having the highest ionisation enthalpy is

Options

A. `[Ne] 3s^2 3p^1 `
B. `[Ne] 3s^2 3p^3`
C. `[Ne] 3s^2 3p^2`
D. `[Ar] 3d^10 4s^2 4p^3`

Answer

B

Explanation

The electronic configuration of options (b) and (d) have exactly half-filled 3d orbitals (b) represents phosphorus and (c) represents arsenic but (b) is smaller in size than (d), Hence, (b) has highest ionisation enthalpy. Ionisation enthalpy increases left to right in the periodic table as the size decreases.