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Cards In This Set
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In 440 BCE, _________ thought that everything was made up of the 4 elements, air,water, earth, fire
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Aristotle & Plato
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In 440 BCE, __________ believed that all matter was made up of teen uncuttable particles called atomos.
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Democritus
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John Dalton (1766-1804)
Dalton's Atomic Theory
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1. All matter is made of atoms
2.Atoms are indivisible
3. An element is only made up of one type of atom
4.Atoms join in Whole # ratios in compounds.
5. Atoms are never created or destroyed in any chemical reaction
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In 1906 __________ proved that atoms are positively charged with negatively charged particles, called electrons, scattered throughout. He showed this in his "Plum Pudding Model" of the atom.
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J.J. Thomson
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Plum Pudding Model of an atom
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 By J.J. Thomson |
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In 1908, ______ proved that an atom is mostly empty space with a VERY smail, dense, +positively charged core, called a nucleus, in the middle, with electrons randomly orbiting it.
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Ernest Rutherford
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Rutherford's Model of an atom
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 Pic: |
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In 1913 __________ said that electrons travel in energy levels around a nucleus. see "the story of the atom" sht.EDIT
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Niels Bohr
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In 1920, ___________ found problems in Niels Bohr's model: an electron's exact location can't be determined since electrons move so quickly. They came up with the electron cloud model.
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DeBrogle & Shrodinger
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Electron Cloud Model
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 darker the shading, the likelier chance of finding an electron. |
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In ____, scientists found that the nucleus is made up of protons, which have a + charge, and neutrons which are neutral.
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 1932 |
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In _________, scientists found that protons and neutrons are held together by particles called mesons.
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 1947 |
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In _____, scientists found that protons and neutrons are made up of quarks and that they're held together by gluons.
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 1968 |
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6 different types of quarks:
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Up, Down, Strange, Charm, Top, and Bottom
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