The atomic weight of silver is 107.868 amu. Naturally occurring silver consists of two isotopes. 107Ag (mass = 106.904 amu) and 109Ag (mass = 108.905 amu). What percentage of naturally occurring silver is the heavier isotope? a. 45.4% b. 52.6% c. 62.7% d. 48.2% e. 51.7%