# Order of Solubility [duplicate]

Why solubility of alkaline earth metals decreases down the group?

In my book, it is given that solubility of earth metals increases down the group

$$\ce{BeSO4 > MgSO4 > CaSO4 > SrSO3 > BaSO4}$$

I couldn't really understand how is this possible.

Can anybody explain?

## 1 Answer

the size (atomic radius) of the element increases. Mg 2+ is a much smaller in size than Ba 2+ because it contains less protons and neutrons in its nucleus. As a result, larger cations form STRONGER bonds with larger anions (CO3 is considered a decent size anion). The rule here is ions of similar size attract one another strongly, and thus do NOT dissociate or become soluble in solution. (used CO3 as example)