A penny is made of the element zinc plated with the element copper; a nickel is made of a mixture of the elements nickel and copper. Some isotopes of various elements are listed below by their atomic number and mass number. Use the periodic table on p. 131 to identify which atoms you would expect to find in the penny, which you would expect to find in the nickel, which you would expect to find in both, and which you would expect to find in neither coin.