Chapter 2, Problem 2B.20E

(a)

Interpretation Introduction

Interpretation:

The Lewis structure of ${\text{SO}}_2$ has to be drawn and the formal charge has to be determined.

Concept Introduction:

Lewis structures represent covalent bonds and describe valence electrons configuration of atoms. The covalent bonds are depicted by lines and unshared electron pairs by pairs of dots. The sequence to write Lewis structure of some molecule is given as follows:

• The central atom is identified and various other atoms are arranged around it. This central atom so chosen is often the least electronegative.
• Total valence electrons are estimated for each atoms.
• single bond is first placed between each atom pair.
• The electrons left can be allocated as unshared electron pairs or as multiple bonds around symbol of element to satisfy the octet (or duplet) for each atom.
• Add charge on overall structure in case of polytatomic cation or anion.

The formal charge on each atom in the Lewis structure can be calculated from the equation written as follows:

    $\text{Formal charge}=\left[V-L-\frac{1}{2}B\right]$

Here,

$V$ denotes valence electrons in free atom.

$L$ denotes electrons present as lone pairs.

$B$ denotes electrons present as bond pairs.

(b)

Interpretation Introduction

Interpretation:

The Lewis structure of ${\text{SO}}_3$ has to be drawn and the formal charge has to be determined.

Concept Introduction:

Refer to part (a).

(c)

Interpretation Introduction

Interpretation:

The Lewis structure of ${\text{SO}}_3^{2-}$ has to be drawn and the formal charge has to be determined.

Concept Introduction:

Refer to part (a).