Chapter 4, Problem 35A

(a)

Interpretation Introduction

Interpretation: The formula for the oxide of potassium element needs to be written.

Concept introduction: Binary ionic compound: A two-element compound consisting of a cation and an anion.

Answer to Problem 35A

  ${\text{K}}_{\text{2}}\text{O}$

Explanation of Solution

The oxide is a binary compound with oxygen and some other element or group. The given element is potassium. The stable charge on potassium or K is +1 as it is an alkali metal. The stable charge on O atom is -2.

To form a stable or neutral compound, K and O must be combined in 2:1 ratio thus, formula will be K₂O.

Element	Ions Present	Formula
Potassium	${\text{K}}^{\text{+}}\text{and}{\text{O}}^{\text{2-}}$	${\text{K}}_{\text{2}}\text{O}$

(b)

Interpretation Introduction

Interpretation: The formula for the oxide of magnesium element needs to be written.

Concept introduction: Binary ionic compound: A two-element compound consisting of a cation and an anion.

Answer to Problem 35A

  $\text{MgO}$

Explanation of Solution

The oxide is a binary compound with oxygen and some other element or group. The given element is magnesium. The stable charge on magnesium or Mg is +2 as it is an alkaline earth metal. The stable charge on O atom is -2.

To form a stable or neutral compound, Mg and O must be combined in 2:2 ratio thus, formula will be MgO.

Element	Ions Present	Formula
Magnesium	${\text{Mg}}^{\text{2+}}\text{and}{\text{O}}^{\text{2-}}$	$\text{MgO}$

(c)

Interpretation Introduction

Interpretation: The formula for the oxide of iron (II) needs to be written.

Concept introduction: Binary ionic compound: A two-element compound consisting of a cation and an anion.

Answer to Problem 35A

  $\text{FeO}$

Explanation of Solution

The oxide is a binary compound with oxygen and some other element or group. The given ion is iron (II). From the name, Fe has +2 charge. The stable charge on O atom is -2.

To form a stable or neutral compound, Fe and O must be combined in 2:2 ratio thus, formula will be FeO.

Element	Ions Present	Formula
Iron(II)	${\text{Fe}}^{\text{2+}}\text{and}{\text{O}}^{\text{2-}}$	$\text{FeO}$

(d)

Interpretation Introduction

Interpretation: The formula for the oxide of iron (III) needs to be written.

Concept introduction: Binary ionic compound: A two-element compound consisting of a cation and an anion.

Answer to Problem 35A

  ${\text{Fe}}_2{\text{O}}_3$

Explanation of Solution

The oxide is a binary compound with oxygen and some other element or group. The given ion is iron (III). From the name, Fe has +3 charge. The stable charge on O atom is -2.

To form a stable or neutral compound, Fe and O must be combined in 2:3 ratio thus, formula will be Fe₂O₃.

Element	Ions Present	Formula	Comments
Iron(III)	${\text{Fe}}^{\text{3+}}\text{and}{\text{O}}^{\text{2-}}$	${\text{Fe}}_2{\text{O}}_3$	2 ${\text{Fe}}^{\text{3+}}$ and 3 ${\text{O}}^{\text{2-}}$ have balanced charges.

(e)

Interpretation Introduction

Interpretation: The formula for the oxide of zinc needs to be written.

Concept introduction: Binary ionic compound: A two-element compound consisting of a cation and an anion.

Answer to Problem 35A

  $\text{ZnO}$

Explanation of Solution

The oxide is a binary compound with oxygen and some other element or group. The given element is zinc. The stable charge on zinc is +2. The stable charge on O atom is -2.

To form a stable or neutral compound, Mg and O must be combined in 2:2 ratio thus, formula will be ZnO.

Element	Ions Present	Formula
Zinc	${\text{Zn}}^{\text{2+}}\text{and}{\text{O}}^{\text{2-}}$	$\text{ZnO}$

(f)

Interpretation Introduction

Interpretation: The formula for the oxide of lead needs to be written.

Concept introduction: Binary ionic compound: A two-element compound consisting of a cation and an anion.

Answer to Problem 35A

  $\text{PbO}$

Explanation of Solution

The oxide is a binary compound with oxygen and some other element or group. The given element is lead. The stable charge on lead is +2. The stable charge on O atom is -2.

To form a stable or neutral compound, Pb and O must be combined in 2:2 ratio thus, formula will be PbO.

Element	Ions Present	Formula
Lead(II)	${\text{Pb}}^{\text{2+}}\text{and}{\text{O}}^{\text{2-}}$	$\text{PbO}$

(g)

Interpretation Introduction

Interpretation: The formula for the oxide of aluminium needs to be written.

Concept introduction: Binary ionic compound: A two-element compound consisting of a cation and an anion.

Answer to Problem 35A

  ${\text{Al}}_{\text{2}}{\text{O}}_{\text{3}}$

Explanation of Solution

The oxide is a binary compound with oxygen and some other element or group. The given element is aluminium. The stable charge on aluminium is +3. The stable charge on O atom is -2.

To form a stable or neutral compound, Al and O must be combined in 2:3 ratio thus, formula will be ${\text{Al}}_{\text{2}}{\text{O}}_{\text{3}}$

Element	Ions Present	Formula
Aluminum	${\text{Al}}^{\text{3+}}\text{and}{\text{O}}^{\text{2-}}$	${\text{Al}}_{\text{2}}{\text{O}}_{\text{3}}$