Answer:
90
Explanation:
To find the number of atoms in a formula, you have to add the number of each element. To find the number of each element, multiply the coefficient by the subscript for each individual element. If an element does not have a subscript, it is equal to 1.
Zn = 15x1 = 15
S = 15x1 = 15
O = 15x4 = 60
60+15+15 = 90 atoms.
