What is the correct formula for calcium sulfate dihydrate?

-Ca (SO4) 2*2H20

-CaSO4 + 2H20

-Ca2SO4.2H20

It is CaSO4.2H2O

Explanation:

Calcium has a valence of 2 because it has only two valency electrons.

Sulphate (SO4) ^2 - is a radical with a valence value of 2.

When Calcium combines with sulphate in bonding,

Formular = => Ca2 (SO4) 2

But the 2 cancel out.

Overall formular==> CaSO4

For hydrated, = => CaSO4. H2O