Chapter 7.3, Problem 20PP

Interpretation Introduction

Interpretation:

Formula for ionic compound formed by magnesium and chloride needs to be determined.

Concept introduction:

Ionic compounds are formed as the result of formation of positive as well as negative ions. Electrons are basically transformed from one atom to other for formation of rare gas electron structure for each ion.

The atom that forms a positive ion will loses electrons to the atom that basically gains electrons for formation of a negative ion.

Answer to Problem 20PP

Formula is ${\text{MgCl}}_{\text{2}}$.

Explanation of Solution

Formula for the ionic compounds formed by magnesium and chloride is ${\text{MgCl}}_{\text{2}}$.

The charge on Mg ion is +2 and that on Cl ion is -1 thus, to from neutral compound, 1 mol of Mg ion should react with 2 mol of Cl ion.

Chemical equation is represented as follows:

${\text{Mg}}^{2+}+2{\text{Cl}}^{-}\to {\text{MgCl}}_{\text{2}}$

Here, 2 electrons from Mg are transferred to 2 Cl atoms (1 electron each).

The electronic configuration can be represented as follows:

Conclusion

Therefore, ${\text{MgCl}}_{\text{2}}$ is the required formula.