Chapter 5, Problem 5ALQ

Interpretation Introduction

(a)

Interpretation:

The general formula for an ionic compound formed by elements in the given groups should be determined and explained with an example.

Concept Introduction:

Ionic compounds are formed by attraction of positive and negative charge ions. An atom of element with high electronegativity can gain electron/s to form negative charge ions and an atom of element with low electronegativity can lose electron/s to form positive charge ions. These negative and positive charged ions combined to form ionic compounds.

Answer to Problem 5ALQ

General formula: $\text{MX}$

Example: NaCl, sodium chloride.

Explanation of Solution

Group 1 elements are alkaline metals, they can give one electron to form positive charged ion with charge + 1.

The general electronic configuration of group 1 elements is $\text{n}{\text{s}}^1$ thus, they can lose this electron to get stable electronic configuration. The formation of positive charge is represented as follows:

$\text{M}\to {\text{M}}^{+}+{\text{e}}^{-}$

Here, M represents the alkali metal.

Similarly, the general electronic configuration of group 7 or VII B(according to old IUPAC) elements is $\text{n}{\text{s}}^2\text{n}{\text{p}}^5$, the elements belong to this group are halogen, they can accept an electron to get the stable electronic configuration. The formation of negative charge is represented as follows:

$\text{X}+{\text{e}}^{-}\to {\text{X}}^{-}$

Here, X represents the halogen.

The ionic compound should be neutral since, there is 1 positive and 1 negative charge, according to crisscross method, they combine in 1:1 ratio and the formula of ionic compound will be:

$\text{MX}$

For example: The ionic compound formed by alkali metal sodium Na and halogen Cl will be NaCl and the name of compound will be sodium chloride.

Interpretation Introduction

(b)

Interpretation:

The general formula for an ionic compound formed by elements in the given groups should be determined and explained with an example.

Concept Introduction:

Ionic compounds are formed by attraction of positive and negative charge ions. An atom of element with high electronegativity can gain electron/s to form negative charge ions and an atom of element with low electronegativity can lose electron/s to form positive charge ions. These negative and positive charged ions combined to form ionic compounds.

Answer to Problem 5ALQ

General formula: ${\text{MX}}_2$

Example: ${\text{MgCl}}_{\text{2}}$, magnesium chloride.

Explanation of Solution

Group 2 elements are alkaline earth metals, they can give two electrons to form positive charged ion with charge + 2.

The general electronic configuration of group 2 elements is $\text{n}{\text{s}}^2$ thus, they can lose these electrons to get stable electronic configuration. The formation of positive charge is represented as follows:

$\text{M}\to {\text{M}}^{2+}+2{\text{e}}^{-}$

Here, M represents the alkali earth metal.

Similarly, the general electronic configuration of group 7 or VII B (according to old IUPAC) elements is $\text{n}{\text{s}}^2\text{n}{\text{p}}^5$, the elements belong to this group are halogen, they can accept an electron to get the stable electronic configuration. The formation of negative charge is represented as follows:

$\text{X}+{\text{e}}^{-}\to {\text{X}}^{-}$

Here, X represents the halogen.

The ionic compound should be neutral since, there are2 positive chargesand 1 negative charge, according to crisscross method, 1 positive charged ion combines with 2 negative charged ions and the formula of ionic compound will be:

${\text{MX}}_2$

For example: The ionic compound formed by alkali earth metal magnesium Mg and halogen Cl will be ${\text{MgCl}}_{\text{2}}$ and the name of compound will be magnesium chloride.

Interpretation Introduction

(c)

Interpretation:

The general formula for an ionic compound formed by elements in the given groups should be determined and explained with an example.

Concept Introduction:

Ionic compounds are formed by attraction of positive and negative charge ions. An atom of element with high electronegativity can gain electron/s to form negative charge ions and an atom of element with low electronegativity can lose electron/s to form positive charge ions. These negative and positive charged ions combined to form ionic compounds.

Answer to Problem 5ALQ

General formula: ${\text{M}}_2\text{Y}$

Example: ${\text{Li}}_{\text{2}}\text{O}$ lithium oxide.

Explanation of Solution

Group 1 elements are alkaline metals, they can give one electron to form positive charged ion with charge + 1.

The general electronic configuration of group 1 elements is $\text{n}{\text{s}}^1$ thus, they can lose this electron to get stable electronic configuration. The formation of positive charge is represented as follows:

$\text{M}\to {\text{M}}^{+}+{\text{e}}^{-}$

Here, M represents the alkali metal.

Similarly, elements in group 6 or VI B (according to old IUPAC) belongs to oxygen family. The general electronic configuration is $\text{n}{\text{s}}^2\text{n}{\text{p}}^4$ thus, they can gain 2 electrons to get the stable electronic configuration.

The formation of negatively charged ion will be as follows:

$\text{Y}+2{\text{e}}^{-}\to {\text{Y}}^{2-}$

Here, Y represents the element from oxygen family.

The ionic compound should be neutral since, there is 1 positive chargeand 2 negative charges, according to crisscross method, 2 positive charged ions combines with 1 negative charged ion and the formula of ionic compound will be:

${\text{M}}_2\text{Y}$

For example, the ionic compound formed between alkali metal Li and oxygen will be ${\text{Li}}_{\text{2}}\text{O}$ and name of the compound is lithium oxide.

Interpretation Introduction

(d)

Interpretation:

The general formula for an ionic compound formed by elements in the given groups should be determined and explained with an example.

Concept Introduction:

Ionic compounds are formed by attraction of positive and negative charge ions. An atom of element with high electronegativity can gain electron/s to form negative charge ions and an atom of element with low electronegativity can lose electron/s to form positive charge ions. These negative and positive charged ions combined to form ionic compounds.

Answer to Problem 5ALQ

General formula: $\text{MY}$

Example: $\text{MgO}$, magnesium oxide.

Explanation of Solution

Group 2 elements are alkaline earth metals, they can give two electrons to form positive charged ion with charge + 2.

The general electronic configuration of group 2 elements is $\text{n}{\text{s}}^2$ thus, they can lose these electrons to get stable electronic configuration. The formation of positive charge is represented as follows:

$\text{M}\to {\text{M}}^{2+}+2{\text{e}}^{-}$

Here, M represents the alkali earth metal.

Similarly, elements in group 6 or VI B (according to old IUPAC) belongs to oxygen family. The general electronic configuration is $\text{n}{\text{s}}^2\text{n}{\text{p}}^4$ thus, they can gain 2 electrons to get the stable electronic configuration.

The formation of negatively charged ion will be as follows:

$\text{Y}+2{\text{e}}^{-}\to {\text{Y}}^{2-}$

Here, Y represents the element from oxygen family.

The ionic compound should be neutral since, there are 2 positive and 2 negative charges, according to crisscross method, they combine in 1:1 ratio and the formula of ionic compound will be:

$\text{MY}$

For example, the ionic compound formed between alkaline earth metal Mg and oxygen will be $\text{MgO}$ and name of the compound is magnesium oxide.