Chapter 1.17, Problem 1.19P

1.

Interpretation Introduction

To draw: The Lewis structures for each of the given compounds.

Interpretation: The Lewis structures for each of the given compounds are to be drawn.

Concept introduction: The Lewis structure shows the connectivity between atoms by identifying the lone pairs of electrons in a compound. Lewis structures are also called Lewis dot structures. The valence electrons around an atom are shown by dots. Bonds between atoms are shown by lines and the lone pair of electrons is shown by a pair of dots.

The rules to draw Lewis structure are given as,

• Determine the electronegativity and the number of valence electrons contributed by each atom.
• Generally lowest electronegativity atom is the central atom.
• Write the skeleton structure of the molecule.
• Use two valence electrons to form each bond in skeleton structure between the central and outer atoms.
• Satisfy the octets of atoms by distributing remaining valence electrons as nonbonding electrons. It is usually best start with the outer atoms.

2.

Interpretation Introduction

To determine: The hybridization, geometry and approximate bond angles around each of the given atom other than hydrogen.

Interpretation: The hybridization and approximate bond angles around each of the given atom other than hydrogen are to be shown.

Concept introduction: The hybridization is a theoretical phenomenon which explains the bonding pattern within the molecule. There are various types of hybridization involved in chemical bonding. Generally three main types are as follows,

• $\text{sp}$
• ${\text{sp}}^2$
• ${\text{sp}}^3$

The bond angles in “$\text{sp}$”, “${\text{sp}}^2$” and “${\text{sp}}^3$” hybridization are $180°,120°$ and $109.5°$ respectively.

Geometry of molecules is decided by three-dimensional representation of the molecules. It involves general shape of the molecules. It also includes bond lengths, bond angles, and other parameters related to the arrangement of electrons like bond pairs and lone pairs. Geometry of the molecules is also decided by hybridization. It is expressed as,

• For carbon and nitrogen with “$\text{sp}$” hybridization it is “linear”.
• For carbon and nitrogen with “${\text{sp}}^2$” hybridization it is “trigonal planar”.
• For carbon and nitrogen with “${\text{sp}}^3$” hybridization the geometry is “tetrahedral” and “pyramidal” respectively.

3.

Interpretation Introduction

To draw: The three-dimensional representations of the given compounds with the representation of wedge and dashed lines.

Interpretation: The three-dimensional diagrams of the given compounds with the representation of wedge and dashed lines are to be drawn.

Concept introduction: The three-dimensional representation of the molecule is described by the type of hybridization present in the molecule. On the basis of hybridization the bonding and non-bonding electrons are calculated. The bonding electrons are represented by single, double or triple bonds. The non-bonding electrons are represented by lone pairs of electron.