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Democritus Atomic Theory
He said all matter is made of atoms. Atoms are indivisible and indestructible. All atoms of a given element are identical in mass and properties. Compounds are formed by a combination of two or more different kinds of atoms. A chemical reaction is a rearrangement of atoms. -
J. Dalton's Atomic Theory
He said all matter is made of atoms. Atoms are indivisible and indestructible. All atoms of a given element are identical in mass and properties. Compounds are formed by a combination of two or more different kinds of atoms. A chemical reaction is a rearrangement of atoms. -
J.J. Thomson "Plum Pudding"
J. J. Thomson discovered the electron in 1897 and put together the "Plum Pudding" model in 1904. He believed that electrons were surrounded by a soup or cloud of positive charge. -
Hantaro Nagaoka Planetary Model
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Bohr Model
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Rutherford's Gold Foil
He used a thin film of gold atoms. Then he shot high velocity particles at it. Most of them passed through, but some were reflected and turned back around. He said that the only way this could happen was if most of an atom's mass was in its nucleus. -
James Chadwick Discovers Neutron
