Chapter 1, Problem 1.26SP

1. a. Draw the resonance forms for SO₂ (bonded O—S—O).
2. b. Draw the resonance forms for ozone (bonded O—O—O).
3. c. Sulfur dioxide has one more resonance form than ozone Explain why this structure is not possible for ozone.

Interpretation Introduction

To determine: The resonating structures of ${\text{SO}}_{\text{2}}$ molecule.

Interpretation: The resonating structures of ${\text{SO}}_{\text{2}}$ molecule are to be stated.

Concept introduction: Resonance is the process in which a molecule gets different structures to define its bonding within the molecule. Such molecules cannot be represented in single Lewis structures. Resonating structures of such molecules are called contributing structures. In the process of resonance, shifting of lone pairs occurs with the bonds and other lone pairs.

Answer to Problem 1.26SP

The resonating structures of ${\text{SO}}_{\text{2}}$ molecule are shown in Figure 1.

Explanation of Solution

The resonating structures of the given molecule are shown as,

Figure 1

The given compound is ${\text{SO}}_{\text{2}}$. Sulfur is present at the centre of the molecule. Two oxygen atoms are arranged around carbon. In first structure, sulfur is present at the centre. It is bonded with two oxygen atoms by double bonds. In second structure, one oxygen atom carries a negative charge with three lone pairs and one oxygen atom carries only two lone pairs of electron. Third structure is same as second one. Only different oxygen are involved. Shifting and movement of electrons, bonds and charges take place to get resonating structures of ${\text{SO}}_{\text{2}}$.

Interpretation Introduction

To determine: The resonating structures of ${\text{O}}_3$ molecule.

Interpretation: The resonating structures of ${\text{O}}_3$ molecule are to be stated.

Concept introduction: Resonance is the process in which a molecule gets different structures to define its bonding within the molecule. Such molecules cannot be represented in single Lewis structures. Resonating structures of such molecules are called contributing structures. In the process of resonance, shifting of lone pairs occurs with the bonds and other lone pairs.

Answer to Problem 1.26SP

The resonating structures of the given molecule are shown in Figure 2.

Explanation of Solution

The resonating structures of the given molecule are shown as,

Figure 2

The given compound is trioxygen. In this molecule, three oxygen atoms are joined together by one double and one single bond. One oxygen atom carries a positive charge and one carries a negative charge. The positive charge, negative charge and a double bond present in conjugation in the given molecule. It results in the resonating structures of ${\text{O}}_3$ molecule.

Interpretation Introduction

To determine: The reason corresponding to the fact that ozone has only two resonating structures, whereas sulfur dioxide has three.

Interpretation: The reason corresponding to the given fact is to be stated.

Concept introduction: Resonance is the process in which a molecule gets different structures to define its bonding within the molecule. Such molecules cannot be represented in single Lewis structures. Resonating structures of such molecules are called contributing structures. In the process of resonance, shifting of lone pairs occurs with the bonds and other lone pairs.

Answer to Problem 1.26SP

The reason corresponding to the given fact is stated below.

Explanation of Solution

Both the sulfur dioxide and ozone molecules are triatomic and both contain atoms of oxygen family. But the resonating structures of sulfur dioxide are more than ozone. The main reason for this is the difference in the group number of the central atom.

In sulfur dioxide, sulfur is present as a central atom, whereas in ozone oxygen atom is present as a central atom. Rest of the surrounding atoms in both the molecules are same. Atomic number of sulfur is sixteen. Whereas, oxygen has the atomic number eight. Therefore, sulfur contains third shell too and it is capable to handle extra bond by using empty “d” orbital and also able to show more resonating structures. This is not the case with ozone molecule. Hence, sulfur dioxide has more resonating structures than ozone molecule.