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Democritus proprosed the existence of atoms. However, technology was quite limited at the time and the concept could not be tested.
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1913 - Bohr further develops the model of the atom by using mathematical models and the laws of quantum physics
1932 - The neutron is finally discovered by James Chadwick. Experiments using kinematics and accurate measurements lead to the discovery of an undetected subatomic particle. -
1804 - John Dalton first develops his theory of atoms and matter. This was done through careful measurement and experiments backed up with evidence.
1897 - JJ Thompson discovered the negatively charged electron. He figured this out by using electric charges in cathode ray tubes.
1911- Rutherford develops the planetary model of the atom. He came to this conclusion by firing alpha particles at thin gold foil.
