In chemistry, a particle is a small portion of matter that can be described by several physical or chemical properties, such as volume, density, or mass. The term encompasses an enormous range of sizes, from subatomic particles such as electrons, protons, and neutrons, to particles large enough to be seen, such as particles of dust floating in sunlight. There is no particular size restriction on defining a particle, and scientists often think of particles as point-like objects that are considered shapeless for theory purposes.

Particles can be classified as atomic and subatomic particles. An atom consists of three subatomic particles: protons, neutrons, and electrons/Atomic_Theory/The_Atom/Sub-Atomic_Particles). Protons and neutrons are located in the nucleus of an atom, while electrons are located outside of the nucleus/Atomic_Theory/The_Atom/Sub-Atomic_Particles). Subatomic particles can only be produced in particle accelerators or cosmic rays and are studied in particle physics.

In summary, a particle in chemistry refers to a small portion of matter that can be described by several physical or chemical properties, and it encompasses an enormous range of sizes from subatomic particles to particles large enough to be seen.