Chapter 9, Problem 9.1P

Interpretation Introduction

Interpretation:

The Lewis model for the formula for the compound that forms between magnesium and nitrogen is to be predicted.

Concept introduction: Lewis structure represents the bonds present between the atoms in a molecule and the valence electrons surrounding the atom in the molecule.

Answer to Problem 9.1P

Solution:

The formula for the compound that forms between magnesium and nitrogen is ${\text{Mg}}_{\text{3}}{\text{N}}_{\text{2}}$ .

Explanation of Solution

The rules for writing the Lewis dot structures are as follows,

• Draw Lewis symbols for atoms and indicate the number of valence electrons by dots around the respective atoms.
• Complete the octet on each atom by gaining or losing electrons and write the charge obtained by gaining or losing electrons at the top right corner of each atom.
• Balance the charge on atoms.

The given atoms are magnesium and nitrogen.
The symbol of magnesium is $\text{Mg}$ and the number of valence electrons in $\text{Mg}$ is $2$ . Its Lewis representation is,

Figure 1

The symbol of nitrogen is $\text{N}$ and the number of valence electrons in $\text{N}$ is $\text{5}$ . Its Lewis representation is,

Figure 2

Magnesium loses $2$ electrons to complete its octet and gets the charge $\text{(}+\text{2)}$ . It is represented as,

Figure 3

Nitrogen gains $3$ electrons to complete its octet and gets the charge $\text{(}-\text{3)}$ . It is represented as,

Figure 4

To balance the charges $\text{3}{\text{Mg}}^{\text{2+}}$ ions and $\text{2}{\text{N}}^{\text{3-}}$ are required.
The final Lewis structure is represented as,

Figure 5

Therefore, the formula of the compound that forms between magnesium and nitrogen is ${\text{Mg}}_{\text{3}}{\text{N}}_{\text{2}}$ .

Conclusion

The formula of the compound that forms between magnesium and nitrogen is ${\text{Mg}}_{\text{3}}{\text{N}}_{\text{2}}$ .