Question
Which of the following compounds does not the violate octet rule?
A.
$$Br{F_5}$$
B.
$$S{F_6}$$
C.
$$I{F_7}$$
D.
$$PCl_4^ + $$
Answer :
$$PCl_4^ + $$
Solution :
$$\eqalign{ & \left( {\text{A}} \right)Br{F_5} = 12\,{\text{electrons}} \cr & \left( {\text{B}} \right)S{F_6} = 12\,{\text{electrons}} \cr & \left( {\text{C}} \right)I{F_7} = 14\,{\text{electrons}} \cr} $$
$$\left( {\text{D}} \right)PCl_4^ + ;$$
$$ = 8\,{\text{electrons}}$$
Hence, except $$PCl_4^ + $$ all molecules violate octet rule.
$$\eqalign{ & \left( {\text{A}} \right)Br{F_5} = 12\,{\text{electrons}} \cr & \left( {\text{B}} \right)S{F_6} = 12\,{\text{electrons}} \cr & \left( {\text{C}} \right)I{F_7} = 14\,{\text{electrons}} \cr} $$
$$\left( {\text{D}} \right)PCl_4^ + ;$$
$$ = 8\,{\text{electrons}}$$Hence, except $$PCl_4^ + $$ all molecules violate octet rule.