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History of the Atom: - Coggle Diagram
History of the Atom:
(460 – 370 BC)
Aristotle believed matter consisted of the four elements: Fire, Water, Earth, and Air.
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1800's
John Dalton believes that all elements are made of identical atoms, and different elements are made of different atoms. He also believed chemical reactions rearranged atoms.
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1897
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The cathode ray tube experiment used a positively charge plate to prove the existence of negative particles (named corpuscles.) Therefore, there must also be positive particles.
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Thomson proposes the existence of negative and positive subatomic particles and creates the plum pudding model.
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1909
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Thomas' student Ernest Rutherford believes atoms are mostly empty space, and the positive charge was located at the center of the nucleus.
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1920's
Niel Bohr proposes the idea that electrons orbit on discreetly separated energy levels. He believed the electrons could move between these levels, releasing photons.
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Modern Day
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The atom truly has evolved over the years, from once believing it was an unbreakable ball to now knowing about the three subatomic particles that make it. The protons and neutrons of the nucleus, the electrons that orbit through the orbitals outside, Atoms make up everything, even elements.
