Question

In which of the following ionization processes, the bond order has increased and the magnetic behaviour has changed ?

• A. $C_2\to C_2^{+}$
• B. $NO\to N{O}^{+}$
• C. $O_2\to O_2^{+}$
• D. $N_2\to N_2^{+}$

Answer 1

The correct option is B $NO\to N{O}^{+}$

A) In $C_2\to C_2^{+}$, an electron is removed from the bonding molecular orbital. So the bond order decreases.
$\Rightarrow C_2\to {\sigma }_{1s}^2{\sigma }_{1s}^{\ast 2}{\sigma }_{2s}^2{\sigma }_{2s}^{\ast 2}{\pi }_{2p_y}^2{\pi }_{2p_x}^2$


B) In $NO\to N{O}^{+}$, an electron is removed from the antibonding molecular orbital. So the bond order increases and nature changes from paramagnetic to diamagnetic.
$\Rightarrow NO\to {\sigma }_{1s}^2{\sigma }_{1s}^{\ast 2}{\sigma }_{2s}^2{\sigma }_{2s}^{\ast 2}{\pi }_{2p_y}^2{\pi }_{2p_x}^2{\sigma }_{2p_z}^2{\pi }_{2p_y}^{\ast 1}$

C) In $O_2\to O_2^{+}$, an electron is removed from the antibonding molecular orbital. So the bond order increases and magnetic property does not change.
$\Rightarrow O_2\to {\sigma }_{1s}^2{\sigma }_{1s}^{\ast 2}{\sigma }_{2s}^2{\sigma }_{2s}^{\ast 2}{\sigma }_{2p_z}^2{\pi }_{2p_y}^2{\pi }_{2p_x}^2{\pi }_{2p_y}^{\ast 1}{\pi }_{2p_x}^{\ast 1}$

D) In $N_2\to N_2^{+}$, an electron is removed from the bonding molecular orbital. So the bond order decreases and nature changes from diamagnetic to paramagnetic.
$\Rightarrow N_2\to {\sigma }_{1s}^2{\sigma }_{1s}^{\ast 2}{\sigma }_{2s}^2{\sigma }_{2s}^{\ast 2}{\pi }_{2p_y}^2{\pi }_{2p_x}^2{\sigma }_{2p_z}^2$