Democratus theorized that the atom was the smallest unit of matter, and was incuttable and indivisible. His theory was that it was just a round ball with no charge
*Actually 350BCE Aristotle did not like Democritus' model of the atom. He was just stupid and said that there were no smallest units of matter and everything was made of Earth, Wind , and Fire.
Discovered several elements, including oxygen and hydrogen. He somewhat believed in Aristotle's Earth, Wind, and Fire theory. Antoine wrote the first table of elements and some of the first textbooks.
John Dalton philososized that the atom cannot be destroyed or created, and created The Atomic Theory of Matter. He thought that all matter was composed of atoms, and that atoms of different elements could bond.
Plum Pudding. John Dalton discovered the Electron. Made the plum pudding model, whish was electron plums sitting in positive pudding
Made atomic model with atom being mostly air with electrons around it. He discovered they flowed with the Cathode Ray experiment, although he originally set out to prove his colluege JJ thompson's theory correct.
Electron cloud theory. electrons orbited nucleus in rings.