Which of the following compounds shows most covalent character?
Which of the following compounds shows most covalent character?
MF
$\mathrm{MCl}$
$\mathrm{MBr}$
MI
Solution
Ionic character of metal halides decreases in the order $\mathrm{MF}>\mathrm{MCl}>\mathrm{MBr}>\mathrm{MI}$, where, $\mathrm{M}$ is a monovalent metal. Smaller the size of anion, greater is the ionic character (Fajan's rule). Therefore, MI has the lowest ionic character.