Order the following solids according to increasing lattice energy.

Question

HgI2, CdCl2, ZnCl2

Now I get how to sort of do it, but I do not get how to do it if I'm looking at its radius if they do not provide it in the question.

Answer 1

As one goes DOWN the periodic table in the same column, the size increases. As one goes across the table in the same row, the size generally decreases.