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Democritus was the first philosopher to propose the existance of the atom calling it the atomus.
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Discovered that metals can be changed onto other substances making them study the particles of metals which led to the atom.
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Proposed that matter has positive and negative charges from his stormy kite flight attached with a metal key experiment.
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Discovered the law of Conservation of Mass.
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Developed the Law of Constant Composition which is the law that mass cannot be gained or depleted through a reaction or experiment.
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John Dalton proposed that matter has positive and negative charges.
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Michael Faraday developed the Laws of Electrolysis which is splitting molecules with electricity.
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Dmitri Mendeleev discovered the Periodic Law which help build the periodic table and the formula for atoms
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William Crookes discovered cathode rays are deflected by electric fields and magnets suggesting a negative charge.
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G.J. Stoney proposed that electricity was made of discrete negative particles he called electrons.
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Discovered radioactivity.
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J.J. Thomson discovered the charge to mass ration of an electron using the Cathode Ray Tube Experiment. This discovery also helped him create the Plum Pudding Model.
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Marie & Pierre Curie discovered that radiation breakes down particles spontaneously which released subatomic particles and radiation in the form of energy.
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Max Planck used the idea of discrete units of energy to explain hot glowing matter. He called these discrete units of energy quanta.
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Hantaro Nagaoka created the Saturnian Model which has flat rings of electrons revolving around a positively charged particle.
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Albert Einstein developed the equation for for energy which is mass times speed of light squared.
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Robet Millikan determined the charge and mass of an electron through the Oil Drop Experiment.
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Ernest Rutherford found that the positive charge and mass of the atom occupied a small volume in the center and the rest was empty space through the Gold Foil Experiment.
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Henry Moseley discovered the atomic number which is the number of protons in an element.
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Francis Aston discovered isotopes.
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Created the Bohr Model
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Louis de Broglie discovered that electrons had a duel nature similar to particles and waves.
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Discovered the Principle of Indeterminancy.
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Erwin Schrodinger discovered the electron cloud.
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Discovered neutrons in the nucleus giving the world the third atomic particle.
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Aristotle proposed that all matter consisted of four elements: earth, air, water, and fire. He also proposed that all matter consisted of four qualities: dryness, hotness, coldness, and wetness.
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