Which property increases down group II from beryllium to barium?

Explanation

Hydroxide solubility rises down the group, so magnesium hydroxide is only sparingly soluble while barium hydroxide dissolves appreciably, whereas the sulphates show the opposite trend and become less soluble. Ionisation energy and electronegativity both fall down a group as the atoms get larger. This contrast between hydroxides and sulphates is a favourite examination point.