Which of the following best describes the relative mass of a neutron compared to a proton?

• A. Approximately equal to the mass of a proton
• B. Much less than the mass of a proton
• C. Twice the mass of a proton
• D. About half the mass of a proton

Answer: (A)

Verified step by step guidance

1. Recall that both protons and neutrons are nucleons, meaning they reside in the nucleus of an atom and have similar masses.
2. Understand that the mass of a proton is approximately 1 atomic mass unit (amu), and the neutron's mass is very close to this value.
3. Note that the neutron's mass is slightly greater than that of the proton, but the difference is very small (on the order of 0.1%).
4. Compare the options given: 'Much less', 'Twice', and 'About half' the mass of a proton are all significantly different from the actual neutron mass.
5. Conclude that the best description is that the neutron's mass is approximately equal to the mass of a proton.