What is the total charge of the polonium nucleus? (the neutral polonium atom has 84 electrons?

Since the polonium atom has 84 electrons, it also has 84 protons. The protons have a positive charge (+1), and are in the nuclueus with the neutrons (no charge). The electrons (charge = - 1) are NOT in the nucleus, but surround it. Thus, the total charge of the polonium nucleus is + 84