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Aristotle didnt think atoms could be constantly moving if they were in a void. He beleived there were four elements and four qualities, and that they would align into their rightful place and be at rest.
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Democritus, a Greek philosopher, co-originated the thought (with his teacher, Leucippus) that all matter is composed of indivisible elements.
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theorized a mechanical universe with small, solid masses in motion.
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Lavoisier was a French nobleman that founded several elements and put the first table of elements together.
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a British chemist and physicist, developed a theory that matter is simply composed of atoms of different weights and is combined in ratios by weight.
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Studied the effect of electricity on solutions, coined term "electrolysis" as a splitting of molecules with electricity, developed laws of electrolysis.
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Built one of the first gas discharge tubes ("cathode ray tube").
The cathode ray tube (CRT) is a vacuum tube containing one or more electron guns, and a fluorescent screen used to view images. -
He discovered that the properties of elements "were periodic functions of the their atomic weights"
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Max Planck introduced what would be known as quantum theory, stating that electromagnetic energy could only be emitted in quantized form. His quanta are now called photons by physicists.
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This man suggested that electrons travel around the nucleus in definite paths. These paths are always at a certain "level" away from the nucleus.
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Electrons are similar to both particles and waves.
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Described atoms by means of formula connected to the frequencies of spectral lines. Proposed Principle of Indeterminancy - you can not know both the position and velocity of a particle.
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Jame Chadwick was an English scientist that discovered the neutron. Before this discovery, Rutherford had concluded that the nucleus was made of positive matter.
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Using alpha particles discovered a neutral atomic particle with a mass close to a proton. Thus was discovered the neutron.
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Otto Hahn, regarded as the father of nuclear chemistry, discovers nuclear fission, along with Lise Meitner.