The mass number of an atom is determined by the number of ____.
A)neutrons and protons
B)neutrons and electrons
C)protons and electrons
D)protons only
E)neutrons only

Question

Quizplus · Accepted Answer

The mass number of an atom is determined by the sum of its protons and neutrons, as electrons have negligible mass in comparison. Therefore, choice A, which includes neutrons and protons, is the correct answer.

The Mass Number of an Atom Is Determined by the Number