#### Answer

$Mg_{3}$$(PO_{4})_{2}$
3 Magnesium atoms, 2 Potassium atoms, 8 Oxygen atoms

#### Work Step by Step

To determine the amount of atoms of each element, one must first determine the amount of elements in the molecule. Each uppercase letter represents a new element. So we have Mg, P, and O elements in the molecule. Then determine the amount of each atom by looking at the subscripts of each element. Therefore, Mg is 3. If there is a molecule that is denoted with a parentheses, then to determine the amount of each element in that molecule, multiply the subscript of the element by the subscript on the outside of the parentheses. Therefore, potassium would be 2, since 1 x 2 = 2 (one original potassium multiplied by 2, since that is the subscript outside the parentheses). Likewise, oxygen would be 4 x 2 = 8.