Bond order normally gives an idea of the stability of a molecular species. All the molecules,namely $H_2$,$Li_2$,and $B_2$,have the same bond order,yet they are not equally stable. Their stability order is:

The species having a bond order different from that in $CO$ is

The wave functions of $1s$-orbitals of two hydrogen atoms are $\psi_A$ and $\psi_B$. $\psi_A$ and $\psi_B$ are linearly combined to form two molecular orbitals ($\sigma$ and $\sigma^*$). Which of the following statements are correct?
$I$. $\sigma^*$ is equal to $(\psi_A - \psi_B)$.
$II$. In $\sigma$-orbital,one nodal plane is present in between two nuclei.
$III$. The energy of $\sigma$-orbital is lower than the energy of $\sigma^*$-orbital.

The set of species having only fractional bond order values is

How many molecular orbitals filled with one or more electrons are present in $N_2^+$?

Give the order of relative stability for $N_2, N_2^+, N_2^-,$ and $N_2^{2+}$.