Bromine has two naturally occurring isotopes, Br-79 and Br-81. The atomic mass of Br-79 is 78.9183 u with a percent abundance of 50.69% and the atomic mass of Br-81 is 80.9163 u. Calculate the atomic mass of bromine.
A) 80.91 u
B) 78.92 u
C) 79.90 u
D) 80.92 u
E) 80.03 u

Question

Quizplus · Accepted Answer

The atomic mass of bromine is calculated using the weighted average of its isotopes: (78.9183 u * 0.5069) + (80.9163 u * 0.4931) = 79.90 u.

Bromine Has Two Naturally Occurring Isotopes, Br-79 and Br-81