Question

How many atoms of each element are present in 1 formula unit of CA3(PO4)2?

Answer 1

CA3(PO4)2

There are 6.02E23 molecules of Ca3(PO4)2 in 1 formula unit.
Multiply by 3 for atoms of Ca
Multiply by 2 for atoms of P
Multiply by 8 for atoms of O
Total atoms = atoms Ca + atoms P + atoms O.