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Democritus asked himself that if he breaks a piece of matter in half, then breaks it in half again, how many more breaks can he make before he could no longer break it. He theorized that the smallest piece of matter is called an atom, a tiny, invsible particle.
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Dalton Laws:
Law of Conservation of Mass- Mass is neither created nor destroyed in a chemical reaction
Law of Constant Composition- A given compound always contains the same elements in the same proportions by mass
Atomic Theory of Matter:
-each element is composed of atoms
-all atoms are specific to the element
-conservation of mass
-a given compound always has the same relative numbers and kinds of atoms -
discovered trends in certain properties of selected groups of elements
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Law od Octaves : "any given element will exhibit analogues behaviour to the eighth element following it in the table"
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Periodic Law:
arranged elements in 7 groups by their similar properties ("periodic functions of their atomic weights") -
published table that releated atomic number and atomic volume
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Discovered electrons using Cathode Ray Tubes
electron charge -1.6021773 x 10^-19 C
electron mass 9.109390 x 10^31 kg -
discovered alpha and beta rays
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used the idea of quanta to explain hot glowing matter
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E=mc^2
Energy=mass x speed of light squared -
created a device that would detect alpha particles
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the positive charge and the mass of an atom is concentrated towards the center of an atom and that the electrons orbit around the atomic center
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discovered that the nucleas was very dense, small, and had a positive charge using fold foil experiment
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created atomic model that depicted orbital electron shells
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discovered neutron
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LA Times- scientists begin discovering new more efficient ways to clean up oil spills. Research was sparked after 1989 oil spill in Alaska.
