Which of the following species is paramagnetic?

Among $KO_2$,$NO_2^-$,$BaO_2$ and $NO_2^+$,an unpaired electron is present in:

Give the electron configuration,bond order,magnetic property,and energy diagram for the beryllium $(Be_{2})$ molecule and discuss its existence.

If an extra electron is added to the hypothetical molecule $C_{2}$,this extra electron will occupy the molecular orbital.

Which of the following linear combinations of atomic orbitals will lead to the formation of molecular orbitals in homonuclear diatomic molecules [internuclear axis in $z$-direction]?

Which of the following statements is not correct?
$I$) Bond length order: $H_2^- = H_2^+ > H_2$
$II$) $O_2^+, NO, N_2^-$ have the same bond order of $2.5$
$III$) Bond order can assume any value including zero up to four
$IV$) $NO_3^-$ and $BO_3^{3-}$ have the same bond order for the $X-O$ bond (where $X$ is the central atom)