Question

Which of the following elements will have highest ionisation energy?

• 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 1

Answer: (B)

$1s^{2}2s^{2}2p^{6}3s^{2}3p^{3}$

Answer 2

: Half – filled orbitals have extra stability.