Chapter 8, Problem 75A

(a)

Interpretation Introduction

Interpretation: The relationship between the percent ionic character of single bonds and the electronegativity difference needs to be explained.

Concept Introduction: An ionic compound is formed between atoms having electronegativity differences. The bond so formed between atoms is known as an ionic bond.

Explanation of Solution

An ionic bond is formed when there is an electronegative difference between two bonded atoms such that an atom with low electronegativity can donate its valence electrons to an atom with high electronegativity.

From the given graph, it can be seen that as the electronegativity difference between two atoms increases, their percentage ionic character also increases; thus, they are directly related to each other. A compound with more difference in electronegativity between bonded atoms will have more percent ionic character of bonds.

(b)

Interpretation Introduction

Interpretation: The electronegativity difference with 50% ionic character needs to be determined.

Concept Introduction: An ionic compound is formed between atoms having electronegativity differences. The bond so formed between atoms is known as an ionic bond.

Explanation of Solution

An ionic bond is formed when there is an electronegative difference between two bonded atoms such that an atom with low electronegativity can donate its valence electrons to an atom with high electronegativity.

From the graph, the 50% ionic character corresponds to the electronegativity difference value of approximately 1.6.

(c)

Interpretation Introduction

Interpretation: The percent ionic character of the bond formed between (1) lithium and oxygen, (2) nitrogen and oxygen, (3) magnesium and chlorine, and (4) nitrogen and fluorine need to be determined.

Concept Introduction: An ionic compound is formed between atoms having electronegativity differences. The bond so formed between atoms is known as an ionic bond.

Explanation of Solution

To determine the percent ionic character of the bond formed between given atoms, the electronegativity difference between the atoms needs to be calculated first.

The electronegativity values for given atoms are as follows:

  $\begin{array}{l}\text{Li}=0.98\\ \text{O}=3.44\\ \text{N}=3.04\\ \text{Mg}=1.31\\ \text{Cl}=3.16\\ \text{F}=3.98\end{array}$

(1) The electronegativity difference between lithium and oxygen atom is calculated as follows:

  $\begin{array}{c}D=3.44-0.98\\ =2.46\end{array}$

In the graph, this value corresponds to the percent ionic character of approximately 80%.

(2) The electronegativity difference between nitrogen and oxygen atom is as follows:

  $\begin{array}{c}D=3.44-3.04\\ =0.4\end{array}$

In the graph, this value corresponds to the percent ionic character of approximately 10%.

(3) The electronegativity difference between magnesium and chlorine atom is as follows:

  $\begin{array}{c}D=3.16-1.31\\ =1.85\end{array}$

In the graph, this value corresponds to the percent ionic character of approximately 60%.

(4) The electronegativity difference between nitrogen and fluorine is as follows:

  $\begin{array}{c}D=3.98-3.04\\ =0.94\end{array}$

In the graph, this value corresponds to the percent ionic character of approximately 20%.