Answer:
72 protons
102 neutrons
72 electrons
Explanation:
Hf has an atomic number of 72. By definition, this means that it has 72 protons.
It also has a mass number of 178. The mass number (A) counts all elements with significant mass (protons and neutrons). Then,
A = p⁺ + n⁰
n⁰ = A - p⁺ = 178 - 72 = 102
Hf has 102 neutrons.
Elemental Hafnium is electrically neutral because it has the same amount of positive charges (protons) and negative charges (electrons). Then, it must have 72 electrons.
