Chapter 24, Problem 24.1P

(a)

Interpretation Introduction

Interpretation:

The oxidation state of oxygen atom in $O_2$ has to be assigned.

Concept introduction:

Rules for assigning oxidation state are given below.

1. 1. Free elements have an oxidation state of $0.$
2. 2. The sum of the oxidation states of all the atoms in a species and net charge on the species must be equal.
3. 3. The alkali metal atoms $\left(Li,Na,K,Rb,andCs\right)$ in compounds have an oxidation state of $+1$.
4. 4. Fluorine atoms have an oxidation state of $-1$.
5. 5. The alkaline-earth atoms $\left(Be,Mg,Ca,Sr,Ba,andRa\right)andZnandCd$ in compounds are always assigned an oxidation state of $+2.$
6. 6. Hydrogen atoms have an oxidation state of $+1.$
7. 7. Oxygen atom have and oxidation state of $-2$.

Explanation of Solution

$O_2$ is a free atom. So oxygen atom has an oxidation state of $0.$

(b)

Interpretation Introduction

Interpretation:

The oxidation state of oxygen atom in $K{O}_2$ has to be assigned.

Concept introduction:

Refer to part (a).

Explanation of Solution

$K$ is an alkali metal so it has an oxidation state of $+1.$  The compound $K{O}_2$ is neutral, therefore in order to balance the charge each oxygen must have $-\mathrm{0.5.}$

(c)

Interpretation Introduction

Interpretation:

The oxidation state of oxygen atom in $N{a}_2{O}_2$ has to be assigned.

Concept introduction:

Refer to part (a).

Explanation of Solution

$Na$ is an alkali metal so it has an oxidation state of $+1.$  The compound $N{a}_2{O}_2$ is neutral, therefore in order to balance the charge each oxygen must have $-1.$

(d)

Interpretation Introduction

Interpretation:

The oxidation state of oxygen atom in $O{F}_2$ has to be assigned.

Concept introduction:

Refer to part (a).

Explanation of Solution

$F$ has an oxidation state of $-1.$  The compound $O{F}_2$ is neutral, therefore in order to balance the charge each oxygen must have $+2.$