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

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

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)

$CN^-$ and $N_2$ are isoelectronic,but $N_2$ is chemically inert compared to $CN^-$. The reason is:

The sum of bond order of $O_2^{+}$,$O_2^{-}$,$O_2$ and $O_2^{2+}$ is equal to

What is the number of unpaired electrons in the $NO$ molecule?