Question

Among the following which one has the highest cation to anion size ratio?

• A. $CsI$
• B. $CsF$
• C. $NaF$
• D. $LiF$

Answer 1

The correct option is B $CsF$

The cation to anion size ratio will be maximum when the cation is of largest size and the anion is of smallest size. Among the given species, $C{s}^{+}$ has maximum size among given cations and $F–$ has smallest size among given anions, thus $CsF$ has highest $\frac{r_c}{r_a}$ ratio.