Answer:
bromine
Explanation:
The atomic mass of bromine (Br) is 79.90. There are two main isotopes at 79 and 81, which average out to the 79.90amu value. The 79 has 44 neutrons and the 81 has 46 neutrons. While it won't change the average atomic mass, scientists have made bromine isotopes with masses from 68 to 97.
