What bond order does $O_2^{2 - }$ have

During the change of $O _{2}$ to $O _{2}^{-}$, the incoming electron goes to the orbital :

Which of the following is paramagnetic ?

Among $\mathrm{H}_2, \mathrm{He}_2^{+}, \mathrm{Li}_2, \mathrm{Be}_2, \mathrm{~B}_2, \mathrm{C}_2, \mathrm{~N}_2, \mathrm{O}_2^{-}$, and $\mathrm{F}_2$, the number of diamagnetic species is (Atomic numbers: $\mathrm{H}=1, \mathrm{He}=2, \mathrm{Li}=3, \mathrm{Be}=4, \mathrm{~B}=5, \mathrm{C}=6, \mathrm{~N}=7, \mathrm{O}=8, \mathrm{~F}=9$ )

Maximum unpaired electrons are present in

Number of paramagnetic oxides among the following given oxides is ..... .

$\mathrm{Li}_{2} \mathrm{O}, \mathrm{CaO}, \mathrm{Na}_{2} \mathrm{O}_{2}, \mathrm{KO}_{2}, \mathrm{MgO}$ and $\mathrm{K}_{2} \mathrm{O}$