Stability of the species $Li_2$,$Li_2^-$ and $Li_2^+$ increases in the order of $:-$

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

In $Cl_2O_7$,the $\pi$-bond between $Cl$ and $O$ is formed by the overlapping of :-

Which of the following molecule$(s)$ show$(s)$ paramagnetic behavior?
$(A) O_2$ $(B) N_2$ $(C) F_2$ $(D) S_2$ $(E) Cl_2$
Choose the correct answer from the options given below:

The linear combination of atomic orbitals to form molecular orbitals takes place only when the combining atomic orbitals:
$A$. have the same energy
$B$. have the minimum overlap
$C$. have same symmetry about the molecular axis
$D$. have different symmetry about the molecular axis
Choose the most appropriate from the options given below:

Which one of the following molecules is expected to exhibit diamagnetic behaviour?