Chapter 7, Problem 109A

Interpretation Introduction

Interpretation:

The formation of magnesium oxide and magnesium nitride needs to be explained when magnesium atoms react with oxygen and nitrogen atoms.

Concept introduction:

Magnesium is found in group 2 in the periodic table. Numerous ionic compounds are binary that means they hold only two different elements. Binary ionic compounds comprise a metallic cation and a nonmetallic anion.

Answer to Problem 109A

Magnesium gives its 2 valence electrons to oxygen atoms. On reaction between magnesium and nitrogen, nitrogen needs three electrons to fulfill its octet. Therefore, it reacts with magnesium in 3:2 ratio.

Explanation of Solution

Atomic number of magnesium is 12 and its electron configuration is as follows:

${\text{Mg=1s}}^{\text{2}}{\text{2s}}^{\text{2}}{\text{2p}}^{\text{6}}{\text{3s}}^{\text{2}}$

Magnesium produces +2 cation by losing its two $\text{3s}$ electrons. Electronic configuration of oxygen is as follows:

${\text{O=1s}}^{\text{2}}{\text{2s}}^{\text{2}}{\text{2p}}^4$

Oxygen needs two electrons to fulfill its octet. Magnesium combined with oxygen to produce magnesium oxide $\left(\text{MgO}\right)$.

Consider the electron configuration of nitrogen. Electronic configuration of nitrogen is as follows:

${\text{N=1s}}^{\text{2}}{\text{2s}}^{\text{2}}{\text{2p}}^3$

Nitrogen needs three electrons to fulfill its octet. Magnesium combined with nitrogen in 3:2 ratio to produce magnesium nitride $\left({\text{Mg}}_{\text{3}}{\text{N}}_2\right)$.

Conclusion

Magnesium reacts with oxygen in 2:2 ratio and reacts with nitrogen in 3:2 ratio.