Answer
Protons: 35
Electrons: 35
Neutrons: 45
Work Step by Step
The problem gives the atomic mass number of the isotope, 80, and shows that the element given is Bromine (as indicated by the symbol Br). First of all, the atomic number of Bromine, as the periodic table shows, is 35. This means that all Zinc isotopes have 35 protons. Next, the atomic mass number states that the atomic mass of this isotope is 80 amu. Because both protons and neutrons weigh one amu while electrons are essentially weightless, this means that there must be 45 neutrons (35 protons+45 neutrons= 80 amu). Finally, the symbol does not indicate a charge on the isotope, meaning that this isotope is neutral. Thus, the number of protons and the number of electrons must be equal, as protons have a +1 charge, electrons have a -1 charge, and neutrons have no charge at all.
