What are sub-atomic particles?

Subatomic particle, also called elementary particle, any of various self-contained units of matter or energy that are the fundamental constituents of all matter. read more

Composite subatomic particles (such as protons or atomic nuclei) are bound states of two or more elementary particles. For example, a proton is made of two up quarks and one down quark, while the atomic nucleus of helium-4 is composed of two protons and two neutrons. read more

Subatomic particles include electrons, the negatively charged, almost massless particles that nevertheless account for most of the size of the atom, and they include the heavier building blocks of the small but very dense nucleus of the atom, the positively charged protons and the electrically neutral neutrons. read more

Particles that are smaller than the atom are called subatomic particles. The three main subatomic particles that form an atom are protons, neutrons, and electrons. The center of the atom is called the nucleus. read more