Which subatomic particle has the least amount of mass?

• A. Proton
• B. Neutron
• C. Alpha particle
• D. Electron

Answer: (D)

Verified step by step guidance

1. Recall the basic subatomic particles: protons, neutrons, and electrons. Each has a characteristic mass and charge.
2. Understand that a proton and a neutron have masses close to 1 atomic mass unit (amu), with the neutron being slightly heavier than the proton.
3. Recognize that an alpha particle is composed of 2 protons and 2 neutrons, so its mass is roughly 4 amu, making it much heavier than individual protons or neutrons.
4. Note that the electron is a fundamental particle with a mass approximately 1/1836 that of a proton, making it significantly lighter than protons, neutrons, or alpha particles.
5. Therefore, by comparing the masses, conclude that the electron has the least amount of mass among the listed particles.