Q.6.57 - An Introduction to General, Organic, and Biological Chemistry

Question

Determine the total number of valence electrons for each of the following.

a. ${\mathrm{H}}_2\mathrm{S}$

b. ${\mathrm{I}}_2$

c. ${\mathrm{CCl}}_4$

Step-by-Step Solution

Answer

a. The total number of valence electrons in ${\mathrm{H}}_2\mathrm{S}$ is $8$.

b. The total number of valence electrons in data-custom-editor="chemistry" ${\mathrm{I}}_2$ is $14$.

c. The total number of valence electrons is data-custom-editor="chemistry" ${\mathrm{CCl}}_4$ is $34$.

Step 1: (a) Given Information

To determine the number of valence electrons in ${\mathrm{H}}_2\mathrm{S}$.

Step 2: (a) Explanation

The electrons that are present in an outermost shell of an atom are known as Valence electrons.

In ${\mathrm{H}}_2\mathrm{S}$, the central atom is sulfur, and the number of valence electrons present in sulfur is 6 while the two hydrogen atoms have one valence electron each.

Thus, the total number of valence electrons in ${\mathrm{H}}_2\mathrm{S}$ is as follows:

$$\begin{gathered} \mathrm{Total} \mathrm{number} \mathrm{of} \mathrm{valence} \mathrm{electrons}=\mathrm{Valence} {\mathrm{e}}^{-} \mathrm{of} \mathrm{S} + 2\times \mathrm{Valence} {\mathrm{e}}^{-} \mathrm{of} \mathrm{H} \\ = 6 {\mathrm{e}}^{-}+ 2\times 1 {\mathrm{e}}^{-} \\ =6 {\mathrm{e}}^{-}+2 {\mathrm{e}}^{-} \\ =8 {\mathrm{e}}^{-} \end{gathered}$$

Hence, the total number of valence electrons in ${\mathrm{H}}_2\mathrm{S}$ are 8.

Step 1: Part (b) Given Information

To determine the number of valence electrons in ${\mathrm{I}}_2$

Step 2: Part (b) Explanation

The electrons that are present in an outermost shell of an atom are known as Valence electrons.

In ${\mathrm{I}}_2$ molecule, there are two iodine atoms, each iodine atom possesses 7 valence electrons.

Thus, the total number of valence electrons in ${\mathrm{I}}_2$ is as follows:

$$\begin{gathered} \mathrm{Total} \mathrm{number} \mathrm{of} \mathrm{valence} \mathrm{electrons}=2\times \mathrm{Valence} {\mathrm{e}}^{-} \mathrm{of} \mathrm{I} \\ = 2\times 7 {\mathrm{e}}^{-} \\ =14 {\mathrm{e}}^{-} \end{gathered}$$

Hence, the total number of valence electrons in ${\mathrm{I}}_2$ are 14.

Step 1: part (c) Given information

To determine the valence electrons of ${\mathrm{CCl}}_4$

Step 2: part (c) Explanation

The electrons that are present in an outermost shell of an atom are known as Valence electrons.

In ${\mathrm{CCl}}_4$, the central atom is carbon, and the number of valence electrons present in carbon is 4 while the four chlorine atoms have seven valence electrons each.

Thus, the total number of valence electrons in ${\mathrm{CCl}}_4$ is as follows:

$$\begin{gathered} \mathrm{Total} \mathrm{number} \mathrm{of} \mathrm{valence} \mathrm{electrons}=\mathrm{Valence} {\mathrm{e}}^{-} \mathrm{of} \mathrm{C} + 4\times \mathrm{Valence} {\mathrm{e}}^{-} \mathrm{of} \mathrm{Cl} \\ = 4 {\mathrm{e}}^{-}+ (4\times 7) {\mathrm{e}}^{-} \\ =4 {\mathrm{e}}^{-}+28 {\mathrm{e}}^{-} \\ =34 {\mathrm{e}}^{-} \end{gathered}$$

Hence, the total number of valence electrons in ${\mathrm{CCl}}_4$ are 34.