Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025
Definition
A proton is a subatomic particle found in the nucleus of an atom that carries a positive electric charge. Its presence, along with neutrons, contributes to the atomic mass of an element.
Related terms
Atom: The smallest unit of matter that retains the identity of the substance composed of protons, neutrons, and electrons.
A neutral (uncharged) subatomic particle found in the nucleus of an atom that contributes to its mass alongside protons but does not affect its electric charge.
Electron: A negatively charged subatomic particle orbiting the nucleus of an atom, balancing the positive charge of protons to determine the chemical properties of an element