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400 BCE
Democritus
Democritus discovered the theory that that all matter is made up of various everlasting indivisible elements which he called atoms. -
John Dalton
John Dalton was an English chemist. He figured out that all elements are composed of atoms. He also discovered that all atoms of the same elements are alike, atoms of different elements are different, and that atoms of different elements combine to form a compound. -
J.J. Thompson
Thompson was a English scientist that discovered an electron that he called cathode rays. He discovered cathode rays when he was experimenting with gas discharge tubes. -
Lord Ernest Rutherford
Ernest discovered that atoms are made of a small positive nucleus and that atoms are mostly empty space by conducting an experiment. The experiment was called the gold foil experiment. He did the experiment by using a thin sheet of gold foil, then he shot alpha particles at the gold foil. Most of the partials went through the foil but a few were deflated. -
Niels Bohr
Niels Bohr was a Danish physicist. He created a model of the atom that looked a lot like the solar system. The electrons go around the nucleus.
