Answer
Protons: 30
Neutrons: 35
Electrons: 30
Work Step by Step
The problem gives the atomic mass number of the isotope, 65, and shows that the element given is zinc (as indicated by the symbol Zn). First of all, the atomic number of Zinc, as the periodic table shows, is 30. This means that all Zinc isotopes have 30 protons. Next, the atomic mass number states that the atomic mass of this isotope is 65 amu. Because both protons and neutrons weight one amu while electrons are essentially weightless, this means that there must be 35 neutrons (30 protons+35 neutrons= 65 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, for protons have a +1 charge, electrons have a -1 charge, and neutrons have no charge at all.
