Chapter 7, Problem 103A

Interpretation Introduction

Interpretation:

The formulas and the name of the oxides formed by the two different ions of cobalt needs to be determined.

Concept introduction:

An ionic compound is comprises of ions arranged in a repeating pattern. The chemical formula for an ionic compound, called a formula unit, indicates the simplest ratio of the ions involved.

Answer to Problem 103A

Formula of oxides of ${\text{Co}}^{\text{2+}}$ is $\text{CoO}$ and name of the compound is cobalt (II) oxide.

Formula of oxides of ${\text{Co}}^{\text{3+}}$ is ${\text{Co}}_2{\text{O}}_3$ and name of the compound is cobalt (III) oxide.

Explanation of Solution

Cobalt is a transition metal and it forms both ${\text{Co}}^{\text{2+}}$ and ${\text{Co}}^{\text{3+}}$. Oxygen is group 16 non-metals and it forms $-2$ anion. Cobalt and oxygen react with in 1:1 ratio and produced $\text{CoO}$. The name of the compound is cobalt (II) oxide. Cobalt reacts with oxygen in 2:3 ratio and produce ${\text{Co}}_2{\text{O}}_3$. The name of the compound is cobalt (III) oxide.

Conclusion

Cobalt is a group 9, d-block elements. The charge of a monatomic ion is called its oxidation number. Cobalt shows two oxidation state +2 and +3.