Given that the molecular mass of bromine is 79.90 grams,which of the following isotopes would you expect to have the greatest natural abundance?
A)Br-79
B)Br-80
C)Br-81
D)Br-82
E)none of the above

Question

Quizplus · Accepted Answer

Natural abundance refers to the percentage of each isotope in a naturally occurring sample of the element. The atomic mass of bromine is the weighted average of the masses of its two most abundant isotopes, Br-79 and Br-81. Since the molecular mass of bromine is closest to Br-80 (which has an atomic mass of 79.90), it is reasonable to expect that Br-80 would have the greatest natural abundance.

Given That the Molecular Mass of Bromine Is 79