He believed matter was composed of fundamentally invisible particles called atomos.
He said an atom can be further subdivided into protons, neutrons, and electrons. He also said an atom is the smallest particle that takes part in chemical reactions.
He concluded that atoms are made of positive cores and negatively charged particles within it.
He said atoms have a small charged nucleus surrounded by largely empty space, and circled by tiny electrons.
He made a model that shows the atom as a small, positively charged nucleus surrounded by orbiting electrons.
He created an equation that helps explain the movement of the electrons.