According to modern atomic theory, the two types of particles that exist in the nucleus of an atom are protons and neutrons. Protons are positively charged, while neutrons have no electric charge (they are neutral). The particles that orbit the nucleus are called electrons, and they carry a negative charge.
These particles are called subatomic particles because they are smaller than atoms. The term "subatomic" refers to any particle that is smaller than an atom, encompassing protons, neutrons, and electrons, along with other elementary particles like quarks and leptons. The existence of these subatomic particles helps explain the structure and behavior of atoms, including their chemical properties.