The nuclear isotope of Bromine, BR that contains 46 neutrons per atom is; ⁸¹Br
<h3>Nuclear Isotopes</h3>
The concept of Isotopes as characterized by the presence of the same number of protons and different number of neutrons, hence, resulting in a different mass number for atoms of the same element also applies to nuclear entities.
On this note, the nuclear Isotope of bromine as described is; ⁸¹Br.