GENERAL KNOWLEDGE

Detailed explanation-1: -The mass number = protons + neutrons. Bromine has a mass number of 80 and 35 protons so 80-35 = 45 neutrons.

Detailed explanation-2: -Atomic Structure Selenium has 34 protons and 45 neutrons in its nucleus giving it an atomic number of 34 and a atomic mass of 79.

Detailed explanation-3: -The number of protons is Z=35 i.e. the atomic number. The number N of neutrons equals the mass number A minus the atomic number Z, i.e. The number of neutrons is 45 . The nuclide 8035Br 35 80 B r has zero net charge.

Detailed explanation-4: -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.