Final answer:
The mass number for an atom of nickel containing 28 protons and 32 neutrons is 60.
Step-by-step explanation:
The mass number of an atom is the sum of the protons and the neutrons in its nucleus.
In this case, the atom of nickel contains 28 protons and 32 neutrons. Therefore, the mass number of the nickel atom is 28 + 32 = 60.
So, the mass number for an atom of nickel containing 28 protons and 32 neutrons is 60.