Which of the following species contains four lone pairs of electrons?

Amongst the following,the total number of species $NOT$ having $8$ electrons around the central atom in its outermost shell is $NH_3$,$AlCl_3$,$BeCl_2$,$CCl_4$,$PCl_5$:

Which of the following represents the incorrect order of bond dissociation energy?

What are the successes and failures of the Lewis theory in explaining chemical bonding?

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 .......... .

In the Lewis dot structure for $NO_2^-$,the total number of valence electrons around the nitrogen atom is $.......$