Bromine (Br) has two stable isotopes, ^79Br and ^81Br and ^79Br has an isotopic mass of 78.918 u and an abundance of 50.69%. What is the isotopic mass of ^81Br?
A) 79.90u
B) 80.92u
C) 81.00u
D) 35.00u
E) not enough information is provided to solve this problem
Answer: B