Which of the following species contain only $\pi \,-\,$ bond but exhibit paramagnetic nature ?
$C_2$
$B_2$
${O_2}^{-1}$
$N_2$
The maximum number of hydrogen bonds formed by a water molecule in ice is
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.
The bond length the species ${O_2},O_2^ + $ and $O_2^ - $ are in the order of
According to $MOT$ which of following is correct
Give electron configuration, bond order and magnetic property, energy diagram in $\mathrm{MO}$ for Helium $\left( {{\rm{H}}{{\rm{e}}_2}} \right)$ molecule.