The atomic weight of gold is accepted as 197g. Avagodro's number says that there are 6.022e23 atoms in 1 mole. Therefore, 6.022e23 atoms weighs 197 g.
So you have 1/197 moles or 0.0051 mol. The number of atoms in 1 gram is 0.0051 x 6.022e23 or about 3.057e21 atoms.hope it helps
