Question
Which of the correct increasing order of lone pair of electrons on the central atom?
A.
$$I{F_7} < I{F_5} < Cl{F_3} < Xe{F_2}$$
B.
$$I{F_7} < Xe{F_2} < Cl{F_2} < I{F_5}$$
C.
$$I{F_7} < Cl{F_3} < Xe{F_2} < I{F_5}$$
D.
$$I{F_7} < Xe{F_2} < I{F_5} < Cl{F_3}$$
Answer :
$$I{F_7} < I{F_5} < Cl{F_3} < Xe{F_2}$$
Solution :
The number of lone pairs of electrons on central atom in various given species are
$$\eqalign{
& {\rm{Species}}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,{\rm{Number of lone}} \cr
& \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,{\rm{pairs on central}} \cr
& \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,{\rm{atom}} \cr
& I{F_7}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,nil \cr
& I{F_5}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,1 \cr
& Cl{F_3}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,2 \cr
& Xe{F_2}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,3 \cr
& {\rm{Thus the correct increasing order is}} \cr
& \mathop {I{F_7}}\limits_0 < \mathop {I{F_5}}\limits_1 < \mathop {Cl{F_3}}\limits_2 < \mathop {Xe{F_2}}\limits_3 \cr} $$