The bond order of $O_2^ + $ is the same as in

Which of the following statement is correct for peroxide ion

$A.$  has completely filled antibonding molecular orbitals
$B.$  is diamagnetic
$C.$   has bond order one
$D.$  is isoelectronic with Neon

Which of the following facts given is not correct ?
$(I)$ Bond length order : $H^-_2 = H^+_2 > H_2$

$(II)\, O^+_2 ,NO,N^-_2$ have same bond order of $2 \frac{1}{2}$

$(III)$ Bond order can assume any value including zero upto four

$(IV)\, NO^-_3$ and $BO^-_3$ have same bond order for $X – O$ bond (where $X$ is central atom)

For diatomic molecules, the correct statement($s$) about the molecular orbitals formed by the overlap to two $2 p_z$ orbitals is(are)

$(A)$ $\sigma$ orbital has a total of two nodal planes.

$(B)$ $\sigma^*$ orbital has one node in the $x z$-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 $x y$-plane containing the molecular axis.

Give electron configuration, bond order, magnetic property and energy diagram for berilium $\left( {{\rm{B}}{{\rm{e}}_2}} \right)$ molecule and writ about it existence.