Question

ion ionic radius
cs+ 167 pm
f− 133 pm
based on the data in the table, which of the following diagrams best depicts the structure of the ionic solid csf?
choose 1 answer:

Explanation:

Step1: Analyze ion - size ratio

The ionic radius of $Cs^+$ is 167 pm and that of $F^-$ is 133 pm. The $Cs^+$ ion is larger than the $F^-$ ion. In an ionic solid, larger cations tend to be surrounded by a greater number of anions to maximize the electrostatic attractions and minimize the repulsions.

Step2: Examine the diagrams

In an ionic lattice of $CsF$, the $Cs^+$ cations should be larger in size compared to the $F^-$ anions in the diagram. Looking at the options, in option A, the cations and anions have a significant size - difference where the cations are larger, which is consistent with the ionic radii of $Cs^+$ and $F^-$. In option B, the cations and anions appear to be of similar size. In option C, the anions seem larger than the cations which is incorrect. In option D, the size - relationship is not consistent with the known ionic radii of $Cs^+$ and $F^-$.

Answer:

A.