elementary particle

physics

Also known as: fundamental particle

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Last updated

July 23, 2026

Quick Summary

Elementary particles are the fundamental building blocks of matter, meaning they cannot be broken down into smaller components. Examples include electrons and quarks. While electrons orbit atoms, quarks form protons and neutrons within the atomic nucleus.1

The Standard Model of particle physics describes these elementary particles and their interactions, excluding gravity. It categorizes particles into quarks and leptons, with six "flavors" of each, arranged in three generations of increasing mass. Everyday matter is composed of the lightest generation: up and down quarks (forming protons and neutrons), electrons, and electron neutrinos.2

Particles like photons and gluons act as "messengers" for fundamental forces, while quarks and leptons constitute matter. All these particles exhibit wave-particle duality, meaning they can behave as both waves and particles depending on the conditions.3

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subatomic particle
Elementary particles
Electrons and quarks contain no discernible structure; they cannot be reduced or separated into smaller components. It is therefore reasonable to call them “elementary” particles, a name that in the past was mistakenly given to particles such as the proton, which is in…
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Electrons and quarks contain no discernible structure; they cannot be reduced or separated into smaller components. It is therefore reasonable to call them “elementary” particles, a name that in the past was mistakenly given to particles such as the proton, which is in…
Read More

charge conservation
Although fundamental particles of matter continually and spontaneously appear, disappear, and change into one another, they always obey the restriction that the net quantity of charge is preserved. When a charged particle changes into a new particle, the new particle inherits the exact charge of the…
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Although fundamental particles of matter continually and spontaneously appear, disappear, and change into one another, they always obey the restriction that the net quantity of charge is preserved. When a charged particle changes into a new particle, the new particle inherits the exact charge of the…
Read More

symmetry
Elementary particles are also said to have internal symmetry; these symmetries are useful in classifying particles and in leading to selection rules. Such an internal symmetry is baryon number, which is a property of a class of particles called hadrons. Hadrons with a baryon number…
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Elementary particles are also said to have internal symmetry; these symmetries are useful in classifying particles and in leading to selection rules. Such an internal symmetry is baryon number, which is a property of a class of particles called hadrons. Hadrons with a baryon number…
Read More