* Atomic Number: Bromine (Br) has an atomic number of 35. This means a neutral bromine atom has 35 protons.

* Neutrality: In a neutral atom, the number of protons (positive charge) is equal to the number of electrons (negative charge).

* Isotopes: The number "81" in bromine-81 refers to the mass number (protons + neutrons). The mass number doesn't change the number of electrons in a neutral atom.

Therefore, bromine-81 has 35 electrons.