Question

Which of the following changes in the respective bond order values are caused by removal of an electron from $N_2$ and $F_2$ molecules?

• A. Decrease by 0.5 In both
• B. Increase by 0.5 In both
• C. Increase by 0.5 in the former and decrease by 0.5 in the latter
• D. Decrease by 0.5 In the former and Increase by. 0.5 in the latter
• E. No change in both

Answer 1

Answer: (D)

Decrease by 0.5 In the former and Increase by. 0.5 in the latter

$N_2$ (total electrons=14)
$\sigma 1s^2,\stackrel{★}{\sigma }1s^2,\sigma 2s^2,\stackrel{★}{\sigma }2s^2,\pi 2P_x^2,\approx \pi 2p_y^2,\sigma 2p_x^2$
$F_2$ (total electrons=18)
$\sigma 1s^2,\stackrel{★}{\sigma }1s^2,\sigma 2s^2,\stackrel{★}{\sigma }2s^2,,\sigma 2p_x^2$
$\pi 2p_x^2\approx \pi 2p_y^2,\stackrel{★}{\pi }2p_x^2\approx \stackrel{★}{\pi }2p_y^2$
For $N_2$, the valence orbital is bonding molecular orbital and for $F_2$, it is antibonding molecular orbital.
So, bond order decrease by 0.5 in the former and increase by 0.6 in the latter.