Which sample contains the least number of atoms?

Question

a. 5 g cobalt

b. 5 g calcium

c. 5 g magnesium

d. 5 g copper

Answer 1

Find moles of each by dividing 5 g by the atomic mass of each element. The one that has the fewest moles will also have the fewest number of atoms since 1 mole of any element has 6.02x10²³ atoms.