Silver has two naturally occurring isotopes with the following isotopic masses: 10747Ag 10947Ag 106.90509 108.9047 The average atomic mass of silver is 107.8682 amu. The fractional abundance of the lighter of the two isotopes is . Silver has two naturally occurring isotopes with the following isotopic masses: Ag Ag 106.90509 108.9047 The average atomic mass of silver is 107.8682 amu. The fractional abundance of the lighter of the two isotopes is . 0.24221 0.48168 0.75783 0.90474 0.51835

The fractional abundance of the lighter isotope = 0.5185

Explanation:

Let  y be the fractional abundance of the lighter isotope

Since total abundance = 100% = 1

Therefore the fractional abundance of heavier isotope = 1 - y

Average atomic mass = sum of isotopic mass * fractional abundance of each isotope

108.9047 (1 - y) + 106.90509 (y) = 107.868 2

108.9047 - 108.9047y + 106.90509y = 107.868

- 108.9047y + 106.90509y = - 108.9047 + 107.868

- 1.99961y = - 1.0367

y = (-1.0367)/(-1.9996)

y = 0.5185

Therefore, the fractional abundance of the lighter isotope = 0.5185

c-14 is carbon-14, or radiocarbon.   it is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons.