timeline: atoms

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The history of the atom

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Democritus (400 bc)

He was a Greek Philosofer who thought that if you were to break an apple into little pieces, you would eventually get to a building block so small you couldn't be able to break it anymore. That building block is called the atom.

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John Dalton (1800's)

Discovered that everything was made out of atoms, and that they were indestructible. After presenting his theory, the scientific theory was invented.

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J.J Thomson (1890's)

He was a physicist who discovered the electron, he used cathode ray tube technology to discover it. He predicted that the atom was filled with a positively charged fluid, and that electrons were floating around.

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Ernest Rutherford (1910's)

He didn't believe that Thomsons model was correct, so he did the gold foil experiment. His proposal was that a big mass of positively charged particles was in the center of the atom, and that the electrons orbited the center like the solar system.

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Niels Bohr (1910's)

He agreed with Rutherford, for his model was just a reiteration of his model. Problems like, "the electrons not colliding with the nucleus" were solved

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James Chadwick (1930's)

Discovered the neutron, which made the atom model finally stable, the atom we use today is just a reiteration of his model.