Question

The correct order of the increasing ionic character is :

• A. $BeC{l}_2<MgC{l}_2<CaC{l}_2<BaC{l}_2$
• B. $BeC{l}_2<MgC{l}_2<BaC{l}_2<CaC{l}_2$
• C. $BeC{l}_2<BaC{l}_2<MgC{l}_2<CaC{l}_2$
• D. $BaC{l}_2<MgC{l}_2<CaC{l}_2<BeC{l}_2$

Answer 1

The correct option is A $BeC{l}_2<MgC{l}_2<CaC{l}_2<BaC{l}_2$

According to Fajan's rule as size of cations increase, their polarising power decrease and thus ionic character increase.
the increasing order of cation is $B{e}^{2+}<M{g}^{2+}<C{a}^{2+}<B{a}^{2+}$.
Thus the polarising power decreases in same order. Hence ionic character increases.
So option (A) is correct.