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400 BCE
Democritus
Democritus made a theory about the atom that everything is made up of atoms. He also predicted that the atom was the smallest particle. He was later proven wrong when the proton,neutron, and electron was discovered. -
John Dalton
John Dalton was the one who discovered the atom. John dalton also created an atomic theory. This theory is still used in chemical thought. His theory has 4 stages and is still used today. He created the first chart of atomic weights -
J.J. Thompson
J.J. Thompson conducted experiments studying rays and going out they were made of different particles. While doing this he discovered the electron. One of the parts in an atom. -
Ernest Rutherford
Ernest found that each atom needs a postive proton in the middle of the atom or nucleus. He found this by conducting his gold foil experiment. -
Erwin Schrodinger
He created another model of the atom. He prodicted that the electrons circle the nucleus in circular orbits. It is based on the solar system. The model is called the Bohr model. -
Nelis Bohr
Nelis found out what happens inside of an atom. He also found out that the number of electrons orbiting the atom determines what element the atom is. He also created a picture of an atom but it is no longer used. -
James Chadwick
James Chadwick discovered the neutron
