Q. In which of the following ionisation processes, the bond order has increased and the magnetic behaviour has changed?
A) $C_{2} \longrightarrow C_{2}^{+}$
B) $NO \longrightarrow NO^{+}$
C) $O_{2} \longrightarrow O_{2}^{+}$
D) $N_{2} \longrightarrow N_{2}^{+}$
Explanation
(b)
$NO \longrightarrow NO^{+}$
$\left( NO^{+} \right)\ Total\ e^{-} = 14$
$\sigma 1s^{2},\ _{\sigma}^{*}1s^{2}\ ,\sigma 2s^{2},\ _{\sigma}^{*}2s^{2}\ ,\ \pi 2p_{x}^{1 + 1} = \ \pi 2p_{y}^{1 + 1}\sigma 2p_{z}^{2}$
Diamagnetic
Bond order = $\ = \frac{10 - 4}{2} = 3$
$(NO)\ Total\ e^{-} = 15$
$\sigma 1s^{2}\ _{\sigma}^{*}1s^{2}\sigma 2s^{2}\ _{\sigma}^{*}2s^{2}\ ,\ \sigma 2p_{z}^{2}\pi 2p_{x}^{1 + 1}\pi 2p_{y}^{1 + 1},\ _{\pi}^{*}2p_{x}^{1} = \ _{\pi}^{*}2p_{y}$
Paramagnetic
Bond order = $\ = \frac{10 - 5}{2} = 2.5$
Electron is taken away from non-bonding molecular orbital that’s why bond order increases.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.