Answer:
D. 80 p+, 124 nº, 78 e-
Step-by-step explanation:
The atomic number of mercury (Hg) is 80, which means it has 80 protons and 80 electrons in a neutral atom. The ion given is Hg2+ which means it has lost two electrons, so the number of electrons is now 80 - 2 = 78.
The mass number of mercury is 204, which means it has 204 nucleons in its nucleus. Since the ion is Hg2+, there are two mercury atoms present. Therefore, the total number of protons is 2 × 80 = 160, and the total number of neutrons is 204 - 160 = 44.
So the answer is D) 80 p+, 124 nº, 78 e-