The atomic mass number of an atom is equivalent to the number of ________.
A) protons
B) neutrons
C) electrons
D) protons and electrons
E) protons and neutrons

Question

Quizplus · Accepted Answer

The atomic mass number is the total number of protons and neutrons in the nucleus of an atom. Electrons do not have any significant mass and hence do not contribute to the atomic mass number. Therefore, the best choice is E, as it represents the sum of the numbers of protons and neutrons in the atom.

The Atomic Mass Number of an Atom Is Equivalent to the Number