Final answer:
The atom of Mercury (Hg) has 80 protons, 80 electrons in a neutral state, and typically around 122 neutrons in the mercury isotope with a mass number of 202, which is the most common isotope.
Step-by-step explanation:
The question is asking for the number of protons, electrons, and neutrons in an atom of Mercury (Hg), with a mass number of 80. Firstly, the number of protons in a mercury atom is equal to its atomic number, which is 80. In a neutral atom, this is also the same as the number of electrons, hence there are 80 electrons in mercury. To find the number of neutrons, the mass number would typically be used, but since '80 Hg' seems to be a confusion between the atomic number and mass number, let's clarify: Mercury’s most common isotope has a mass number of about 202. This means it has around 202 - 80 = 122 neutrons. However, since the atomic mass of mercury is not exactly 200 and is actually 200.59, it indicates that the average number of neutrons in mercury isotopes is slightly more than 120.