text: A 2006 US cent weighs 2.5 g and is 2.4% copper, so the total weight of copper is 0.060g.\n\nso the calculation would be:\n\n(0.06g copper) / (63.546g/mol copper) * (6.02214*10^23 atom/mol copper) = 5.69*10^20 atoms copper\n\nP.S. - in response to emetalshop above, a penny is not made from an alloy, it consists of a zinc slug with a thin layer of copper plating.  The percentages by weight are 97.6% zinc and 2.4%copper.