Question

How many bonding pairs and lone pairs surround the central atom in the $I_3^{-}$ ion ?

• A. $2,2$
• B. $2,3$
• C. $3,2$
• D. $4,3$

Answer 1

The correct option is B $2,3$

$H=\frac{1}{2}[V+M-C+A]$
where,
H= Number of orbitals involved in hybridization.
V=Valence electrons of the central atom.
M- Number of monovalent atoms linked to a central atom.
C= Charge of a cation.
A= Charge of an anion.
Consider the hybridization and shape of the options:-
A) $I_3^{-}$
$H=\frac{1}{2}[7+2+1]=5$.
$\Rightarrow s{p}^{3}d$ hybridized state with 3 lone pairs.
Linear in shape.
It has 2 bond pairs.