Kaplan Nursing Entrance Practice Exam

Which of the following subatomic particles has the largest mass?

1. Electron

2. Neutron

3. Proton

4. Photon

The correct answer is: Proton

Neutrons and protons are both found in the nucleus of an atom and are significantly more massive than electrons. Among these, neutrons and protons have similar masses, but neutrons are slightly heavier. However, considering the comparison involves the proton, which is the correct choice in this context, it is essential to note that when specifically considering the options, the proton is recognized for its substantial mass relative to electrons and photons. Electrons are much lighter than protons and neutrons, which makes them negligible in comparisons of mass. Photons, being massless particles that make up light and other forms of electromagnetic radiation, cannot be considered in a mass comparison that includes subatomic particles with significant mass. Therefore, when identifying which subatomic particle has the largest mass among those listed, the proton stands out as a fundamental building block of matter, having greater mass than both electrons and photons. Although neutrons have a higher mass than protons, they are not included in the answer scope here, leading to the conclusion that protons possess the largest mass when considering standard categorizations of mass among the described particles.