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

In dinitrogen tetroxide $(N_2O_4)$,there:

The pair of species with the same bond order is

Which of the following is paramagnetic?

How do you express the bond strength in terms of bond order?

For diatomic molecules,the correct statement$(s)$ about the molecular orbitals formed by the overlap of two $2p_z$ orbitals is(are):
$(A)$ $\sigma$ orbital has a total of two nodal planes.
$(B)$ $\sigma^*$ orbital has one node in the $xz$-plane containing the molecular axis.
$(C)$ $\pi$ orbital has one node in the plane which is perpendicular to the molecular axis and goes through the center of the molecule.
$(D)$ $\pi^*$ orbital has one node in the $xy$-plane containing the molecular axis.