Fill in the blanks:
$(i)$ In $1927$,Heitler and London proposed the ........ theory.
$(ii)$ The ${\rm{ClF}}_3$ molecule has a .... shape.
$(iii)$ The number of bonding pairs in ions with a square planar shape is .......... .
$(iv)$ The value of the dipole moment in ${\rm{HBr}}$ is .......... .

Total number of compounds / ions which have at least two bond lengths same out of $CO_3^{2-}, HCOOH, S_2O_3^{2-}, NO_2^{-}$

The Born-Haber cycle is used to determine:

Select true or false statements :
$(a)$ Promotion of electron is essential condition prior to hybridisation
$(b)$ In $VSEPR$ theory,two or three electron pairs of a multiple bond are treated as a single super pair
$(c)$ Bond length for $CO_2$ lies between double and triple bonds
$(d)$ $Ne_2$ does not exist

The total number of lone pairs of electrons in $N_2O_3$ is

Which of the following sets is not isoelectronic?