Which statement correctly describes a proton?

• A. Has a positive charge and is located in the nucleus
• B. Has no charge and is located in the nucleus
• C. Has a negative charge and orbits the nucleus
• D. Is a massless particle that mediates forces

Answer: (A)

Protons are positively charged subatomic particles that reside in the atomic nucleus. This positive charge (+1e) and their location in the nucleus are defining features, along with neutrons, of the dense center of atoms. Electrons, which are negatively charged, orbit the nucleus outside it, not inside. Protons are massive compared with electrons and are not massless particles that mediate forces; those force carriers (like photons or gluons) have different roles in physics. So the description that best fits a proton is that it has a positive charge and is located in the nucleus.