Question

Can you compare the lattice enthalpies of the salts `MgCl_2`, and `CaCl_2`, and `SrCl_2`, and `BaCl_2`?

Answer 1

Neither `CsCl_2` nor `ScCl_2` exist..........

Explanation:

We could compare `MgCl_2`, and `CaCl_2`, and `SrCl_2`, and `BaCl_2`. Of these, `MgCl_2` will have the highest lattice energy. Why?

Because `Mg^(2+)` is the smallest ion, and thus the electrostatic force of attraction is GREATEST between the smaller metal cation and the chloride anion. And certainly, given the `1/r^2` electrostatic force, interaction between the cation and the anion will be here the most significant.