Why do $N_2$,$NO^+$,$CN^-$,and $CO$ have the same bond order?

Which of the following pairs of species have unpaired electrons in antibonding Molecular Orbital?

The bond energies in $NO$,$NO^{+}$,and $NO^{-}$ follow the order:

The electronic configuration of the $N_2$ molecule in its ground state can be written as: $KK[\sigma 2s^2 \sigma^* 2s^2 \pi 2p_x^2 \pi 2p_y^2 \sigma 2p_z^2]$. What is the bond order of the $N_2$ molecule?

Among the following,the species with identical bond order are

Compare the relative stability of the following species and indicate their magnetic properties: $O_2$,$O_2^+$,$O_2^-$ (superoxide),$O_2^{2-}$ (peroxide).