Question

Arrange the following in increasing order of their covalent character.
A. $CaF_2$
B. $CaCl_2$
C. $CaBr_2$
D. $Cal_2$

• A. B < A < C < D
• B. A < B < C < D
• C. A < B < D < C
• D. A < C < B < D

Answer 1

Answer: (B)

A < B < C < D

Answer 2

From Fajan’s rule, for a given metal ion, as the size of anion increases, polarizability of anion increases and hence covalent character of the given ionic compound increases.

Hence, the increasing order of covalent characters is:

$CaF_2< CaCl_2< CaBr_2< Cal_2$