posted by Josh .
Order the following solids according to increasing lattice energy.
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.
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.