Question

Which has the lowest anion to cation size ratio?

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

Answer 1

The correct option is D $CsF$

Since the ration of $\frac{anion}{cation}$ should be minimum, anion should be the smallest and the cation should be the largest.

Fluoride ion is smaller than iodide ion and Cs+ ion is larger than the others.

Hence, CsF has the lowest anion to cation size ratio.