The Mass Number of an Atom is the Number Of

Question

The mass number of an atom is the number of
A) electrons plus neutrons in the atom.
B) neutrons in the atom.
C) neutrons plus protons in the atom.
D) protons in the atom.
E) protons plus electrons in the atom.

Accepted Answer

The mass number of an atom is defined as the total number of neutrons plus protons in the atom's nucleus. Therefore, choice C, neutrons plus protons in the atom, is the correct answer.