How many of the following species are diamagnetic? $He_2^{+}, H_2, H_2^{+}, H_2^{-}, He$

Of the species,$NO$,$NO^{+}$,$NO^{2+}$,$NO^{-}$,the one with minimum bond strength is:

Give the electron configuration,magnetic property,bond order,and energy diagram for the Nitrogen $(N_{2})$ molecule.

Consider the following changes $I$ and $II$ as shown in the figure. The correct statements about these changes $(I)$ and $(II)$ in accordance with $MO$ theory are:
$A$) In $(I)$ bond order increases by $0.5$ from the existing value.
$B$) In $(II)$ bond order decreases by $0.5$ from the existing value.
$C$) In both $(I)$ and $(II)$ magnetic property is changed.
$D$) In both $(I)$ and $(II)$ magnetic property is not changed.

In which of the following processes does the value of bond order and magnetic nature not change?

Total number of electrons present in $(\pi^*)$ molecular orbitals of $O_2$,$O_2^{+}$,and $O_2^{-}$ is ............