The nucleus of helium-4 contains
A) one proton
B) one proton and one neutron
C) two protons and one neutron
D) two protons and two neutrons
E) three protons and two neutrons

Question

Quizplus · Accepted Answer

Helium-4 has an atomic number of 2, which means it has two protons in its nucleus. It also has a mass number of 4, indicating that there are two additional subatomic particles in its nucleus. Since the atomic mass of a proton is approximately equal to the atomic mass of a neutron, we can reason that helium-4 contains two protons and two neutrons in its nucleus. Therefore, choice D is the best answer.

The Nucleus of Helium-4 Contains