Thank you for reporting, we will resolve it shortly
Q.
The paramagnetism of $O^{+}_{2}$ is due to the presence of an odd electron in the MO
KEAMKEAM 2006Chemical Bonding and Molecular Structure
Solution:
The electronic configuration of oxygen molecule ion is as
$O^{+}_{2} : KK \sigma 2s^2, \sigma^*2s^2, \sigma 2p^{2}_{z}, \pi 2p^2_x \approx\pi 2p^2_y,\pi^*2p^1_x$
Due to the presence of an odd electron in the $\pi^* 2p_x $ molecular orbital, $O^+_2$ is paramagnetic.