$A$ pair of isoelectronic species having bond order of $1$ is

How many ions of the following have a bond order of $2.5 ?$
$N_2^{-} ; NO^{-} ; C_2^{-} ; N_2^{+} ; C_2^{2-} ; CN^{+}$

Molecular orbital theory was developed mainly by

Which of the following molecules contains the maximum number of electrons in antibonding molecular orbitals?

The correct set of symbols for the molecular orbitals given below is:

Consider the following statements.
$I$. In the conversion of $O_2$ to $O_2^{2+}$,bond order decreases.
$II$. In the conversion of $O_2$ to $O_2^{2+}$,magnetic property is not changed.
$III$. In the conversion of $O_2$ to $O_2^{2+}$,bond length decreases.
$IV$. $O_2^{2-}$ and $B_2$ have same bond order.
Identify the correct statements.