Question

Which of the following order of ionization energy is correct?

• A. B < Be < N < C
• B. Be > B > C > N
• C. B < Be < C < N
• D. Be < B < C < N

Answer 1

Answer: (C)

B < Be < C < N

Answer 2

Ionisation energy generally increase in a period from left to right. But due to comparatively stabler configuration of Be $\left(1 s^{2},\, 2 s^{2}\right)$, it has more ionisation energy than Boron $\left(1 s^{2},\, 2 s^{2},\, 2 p^{1}\right)$. Hence, the correct order is : $B < Be < C < N$