Chapter 4, Problem 15P

For each pair of compounds, classify the bonding as ionic or covalent and explain your choice.

1. LiCl and HCl
2. KBr and HBr

Interpretation Introduction

(a)

Interpretation:

The bonding between LiCl and HCl should be classified as ionic or covalent.

Concept Introduction:

The electronegativity difference can be used to differentiate bonds as polar, polar covalent and ionic bonds in different compounds.

If the electronegativity difference between two atoms is 0.5 or less, the bond is nonpolar in which electrons are equally shared. If the electronegativity difference is between 0.5 − 1.9, the bond is polar covalent, in which electrons are unequally shared, they are pulled towards the more electronegative atom. If the electronegativity difference is 1.9 or greater, the bond is ionic which is formed by complete transfer of electron from positive to negative ion.

In common, non-polar and polar bonds are known as covalent bonds where electrons are shared between two atoms.

Answer to Problem 15P

LiCl − ionic

HCl - covalent

Explanation of Solution

Electronegativity values,

Li − 1.0

H − 2.1

Cl − 3.0

Electronegativity difference between Li and Cl = $3.0-1.0=2.0$ . Electronegativity difference is greater than 1.9. so, the bond is ionic.

Electronegativity difference between H and Cl = $3.0-2.1=0.9$ . Electronegativity difference is less than 1.9. so, the bond is covalent.

Interpretation Introduction

(b)

Interpretation:

The bonding between KBr and HBr should be classified as ionic or covalent.

Concept Introduction:

The electronegativity difference can be used to differentiate bonds as polar, polar covalent and ionic bonds in different compounds.

If the difference in electronegativity between two atoms is 0.5 or less, the bond is nonpolar in which electrons are equally shared. If the difference in electronegativitybetween two atoms is between 0.5 − 1.9, the bond is polar covalent, in which electrons are unequally shared, they are pulled towards the more electronegative atom. If the difference is 1.9 or greater, the bond is ionic which is formed by complete transfer of electron from positive to negative ion.

In common, non-polar and polar bonds are known as covalent bonds where electrons are shared between two atoms.

Answer to Problem 15P

KBr − ionic

HBr − covalent

Explanation of Solution

Electronegativity values,

K − 0.8

H − 2.1

Br − 2.8

Electronegativity difference between K and Br = $2.8-0.8=2.0$ . Electronegativity difference is greater than 1.9. so, the bond is ionic.

Electronegativity difference between H and Br = $2.8-2.1=0.7$ . Electronegativity difference is less than 1.9. so, the bond is covalent.