Atoms, molecules and stoichiometry — practice question

Nickel accounts for $20\%$ of the coin’s total mass. The coin has a mass of $10.0\,\text{g}$. How many nickel atoms are in the coin?

• A$2.05 \times 10^{22}$
• B$4.30 \times 10^{22}$
• C$1.03 \times 10^{23}$
• D$1.20 \times 10^{24}$