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(460 B.C.) Democritus decided that all mater was made of tiny indivisible particles. These particles were shaped differently based on the proporties of the substance which they created.
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(384 B.C.) Aristotole belived that the universe was made of four qualities that described all substances. They were dryness, wetness, heat and cold.
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created the law of deffinite poportions, which stated that the same amounts of the same element have the same number of elements in them.
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John Dalton discovered that different elements had different masses. He also stated that one mass unit was equal to one hydrogen atom.
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While trying to prove that x-rays were emited with light, Henri accidentally discovered radiation, when he placed uranium on wave sensitive plates.
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Thomson created the Plum pudding model of an atom, in which there is a cloud of protons and electrons. He discoved electrons simultaniously.
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Rutherford discovered forms of radio active decay, including alpha and beta decay. He sugessted a model of an atom, where teh mass was located in the center nucleus.
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In 1913 Neils Bohr created his theory of atomic structure, which was a planetary model of electrons around the neucleus of an atom.
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he found the correct chrge and mass of electrons.
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this is when Max Planck wn the nobel prize for the origin of Quantm theory.
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Heisenberg intorduced the matrix mechanics model. It was too complicated, and rejected.
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Schrodinger treated atoms as waves rather than as mass, called waves of mass. He also created Schrodinger's equation which shows the behavior of these waves
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de Broglie created an equation specifing the wave length based on planck's constant diveded by the momentum of the electron.
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James chadwick first discovered the neutron in the neucleus. He observed its neutral charge, and its weight.
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(44 bc)
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This is the dynasty from which Korea derrived its name