An atom is the smallest unit of a chemical element that retains the chemical properties of that element.
Subatomic particles are the smallest particles that makeup matter. They include:
An electron is a subatomic particle that carries a negative charge and orbits around the nucleus of an atom.
A proton is a subatomic particle that carries a positive charge and is found in the nucleus of an atom.
A neutron is a subatomic particle found in the nucleus (centre) of an atom, along with protons with a neutral charge.