Amongst the following elements (whose electronic configuration an given below) the one having highest ionization energy is

Options

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

Answer

B

Explanation

Elements having half-filled valence subshell have high ionisation energy. Also, ionisation energy decreases down the group.