According to molecular orbital theory, the number of unpaired electron(s) in $\mathrm{O}_{2}^{2-}$ is :

Number of molecules having bond order $2$ from the following molecule is. . . . . . .  $\mathrm{C}_2, \mathrm{O}_2, \mathrm{Be}_2, \mathrm{Li}_2, \mathrm{Ne}_2, \mathrm{~N}_2, \mathrm{He}_2$

Correct decreasing order of bond order of oxygen species in $I$ to $IV$

$(I)$   $Na_2O_2$

$(II)$  $O_2 [AsF_6]$

$(III)$  $CsO_2$

$(IV)$  $O_2$

The total number of anti bonding molecular orbitals, formed from $2 \mathrm{~s}$ and $2 \mathrm{p}$ atomic orbitals in a diatomic molecule is_______

Given below are two statements:

Statement $(I)$ : A $\pi$ bonding $MO$has lower electron density above and below the inter-nuclear asix.

Statement $(II)$ : The $\pi^*$ antibonding $MO$ has a node between the nucles.In the light of the above statements, choose the most appropriate answer from the options given below:

The molecule in which hybrid $MOs$ involve only one $d-$orbital of the central atom is