Chapter 1.5, Problem 1.9E

(a)

Interpretation Introduction

Interpretation:Whether the arrows representing the movement of electrons in molecules A to D leading to a resonance form is correct or not needs to be determined.

Concept Introduction:VSEPR theory stands as Valence Shell Electron Pair Repulsion Theory. It helps to predict the molecular shape or geometry of the molecule with the help of the number of bond pair or lone pair present in it. According to VSEPR theory, the presence of lone pair on the central atom of molecule causes deviation from standard molecular geometry.

The resonance is the phenomenon in which if all the properties cannot explain by one structure, it can be shown in two or more structures by the shifting of pi bonds or lone pair but there is no change in sigma bond and position of atoms.

(b)

Interpretation Introduction

Interpretation:Thetwo resonance forms of nitrite ion ${\text{NO}}_{{}_{\text{2}}}^{-}$ needs to be drawn with its geometry.

Concept Introduction:VSEPR theory stands for Valence Shell Electron Pair Repulsion Theory. It helps to predict the molecular shape or geometry of the molecule with the help of the number of bond pair or lone pair present in it. According to VSEPR theory, the presence of lone pair on the central atom of molecule causes deviation from standard molecular geometry. This is because of the repulsion between lone pairs and bond pairs of the central atom of the molecule. The order of repulsion is:

Lone pair-lone pair > lone pair-bond pair > bond pair-bond pair

Based on the number of lone pair and bond pair, the molecular geometry can be determined with the help of below table.

Number of hybridizations	Bond pair	Lone pair	Geometry
2	2	0	Linear
2	1	1	Linear
3	3	0	Trigonal planar
3	2	1	Bent
4	4	0	Tetrahedral
4	3	1	Trigonal pyramidal
4	2	2	Bent
5	5	0	Trigonal bipyramidal
5	4	1	See saw
5	3	2	T shaped
5	2	3	Linear
6	6	0	Octahedral

(c)

Interpretation Introduction

Interpretation:TheLewis octet and valence shell expanded resonance forms of ${\text{SO}}_{\text{2}}$ needs to be drawn with consideration of Lewis structure and bond length of S-O in ${\text{SO}}_{\text{2}}$ and $\text{SO }$ . Also comprehended the best possible structure of it.

Concept Introduction:VSEPR theory stands as Valence Shell Electron Pair Repulsion Theory. It helps to predict the molecular shape or geometry of the molecule with the help of the number of bond pair or lone pair present in it. According to VSEPR theory, the presence of lone pair on the central atom of molecule causes deviation from standard molecular geometry. This is because of the repulsion between lone pairs and bond pairs of the central atom of the molecule. The order of repulsion is:

Lone pair-lone pair > lone pair-bond pair > bond pair-bond pair

Based on the number of lone pair and bond pair, the molecular geometry can be determined with the help of below table.

Number of hybridization	Bond pair	Lone pair	Geometry
2	2	0	Linear
2	1	1	Linear
3	3	0	Trigonal planar
3	2	1	Bent
4	4	0	Tetrahedral
4	3	1	Trigonal pyramidal
4	2	2	Bent
5	5	0	Trigonal bipyramidal
5	4	1	See saw
5	3	2	T shaped
5	2	3	Linear
6	6	0	Octahedral