Hydroxides — solubility increases down: Mg(OH)2 (insoluble) → Ba(OH)2 (soluble). Reason: for OH^- (small anion), lattice energy decreases faster than hydration energy as cation size increases, so Delta_sol G becomes more negative. Sulphates — solubility decreases down: MgSO4 (soluble) → BaSO4 (insoluble). Reason: for SO4^2- (large anion), hydration energy decreases faster than lattice energy as cation size increases. Carbonates — all insoluble (lattice energy dominates for moderate-sized CO3^2-). Fluorides — solubility increases down: BeF2 (soluble) → BaF2 (insoluble) — wait, actually: BeF2 soluble, MgF2 slightly soluble, CaF2 insoluble. The trend for fluorides (small anion) matches hydroxides. For large anions (SO4^2-, CO3^2-, CrO4^2-), solubility generally decreases down.