Chapter 2, Problem 2D.2AST

Interpretation Introduction

Interpretation:

Out of the compounds $\text{NaBr}$ and ${\text{MgBr}}_2$ the bonds that have greater covalent character has to be chosen.

Concept Introduction:

In any polar covalent bond, the difference in electronegativities gives rise to partial positive and negative charges respectively on the cation and anions.

The covalent character is determined with respect to the relative extent of distortion of the anionic cloud of the anion. For instance, highly charged small alkali metal cation such as ${\text{Li}}^{+}$ is capable to cause polarization in large-sized halides such as iodide ion. Thus there is a considerable covalent character in $\text{LiI}$.

In general, the greater is the charge on the alkali metal cation or smaller is the size of cation more is its polarizing power to distort the electron cloud of the anion.