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Q.
The bond order in $O^{2-}_2$ is
KVPYKVPY 2010Chemical Bonding and Molecular Structure
Solution:
Total number of electrons in $O^{2-}_2=18 $
The electronic configuration of $O^{2-}_2$
will be $\sigma ls^2\,\sigma^*ls^2\,\sigma2s^2\,\sigma^*2s^2\,\sigma2p^2_z$
$\pi2p^2_x\,\pi2p^2_y\pi^*\,2p^2_x\pi^*\,2p^2_y$
Bond order of a diatomic molecule is
given by the formula, $BO=\frac{N_{b}-N_{a}}{2} $
Bond order of $O^{2-}_2$ will be$\frac{10-8}{2}=1$