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Sir Isaac Newton writes about the possible existence of unseen electrical forces of attraction that hold matter together.
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Most scientists at this time accepted the modern defiinition of an element: a substance that cannot be broken down into any simpler substances.
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John Dalton explains the law of conservation of mass, the law of definite proportions, and the law of multiple proportions in his Atomic Theory.
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Dmitri Mendeleev aranged 7 elements into groups according to atomic mass and chemical properties.
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Later, Thomson's experiments are replicated, leading to the discovery of subatomic particles.
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Robert Millikan discovers the electron
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Ernest Rutherford, Hans Geiger, and Ernest Marsden discover the nucleus. During an experiment, Rutherford aimed alpha particles at a thin gold foil, expecting them to pass through the foil. Most of the particles did, but a small quantity "bounced back," suggesting that the particles bounced off of something in the gold foil.
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Niels Bohr proposed a model often compared to the solar system. He believed that electrons orbited the nucleus like the planets orbit the sun.
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Ernest Rutherford names the positively charged particle of an atom the "proton"
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Idea of the neutron is proposed by Ernest Rutherford
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James Chadwick proves that neutral particles in atoms, neutrons, exist.
