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

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.

According to $MO$ theory, number of species/ions from the following having identical bond order is $.........$

$CN ^{-}, NO ^{+}, O _{2}, O _{2}^{+}, O _{2}^{2+}$

Among $\mathrm{H}_2, \mathrm{He}_2^{+}, \mathrm{Li}_2, \mathrm{Be}_2, \mathrm{~B}_2, \mathrm{C}_2, \mathrm{~N}_2, \mathrm{O}_2^{-}$, and $\mathrm{F}_2$, the number of diamagnetic species is (Atomic numbers: $\mathrm{H}=1, \mathrm{He}=2, \mathrm{Li}=3, \mathrm{Be}=4, \mathrm{~B}=5, \mathrm{C}=6, \mathrm{~N}=7, \mathrm{O}=8, \mathrm{~F}=9$ )

In which of the following transformations, the bond order has increased and the magnetic behaviour has changed ?

Which of the following options represents the correct bond order?