Which of the following element will have highest ionization energy?

Options

A. `1s^(2)2s^(2)2p^(6)3s^(1)`
B. `1s^(2)2s^(2)2p^(6)3s^(2)3p^(3)`
C. `1s^(2)2s^(2)2p^(6)3s^(2)3p^(4)`
D. `1s^(2)2s^(2)2p^(6)3s^(2)3p^(1)`

Answer

B

Explanation

Half-filled orbitals have extra hence they have high ionisation energy.