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460 BC
Democritus came up with the idea and name of the atom; although, his ideas were ridiculed, even by Aristotle. -
1800's
John Dalton did many experiments with chemicals that all pointed to the idea that there were small particles in matter. -
He built one of the first cathode-ray tubes.
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James Clerk Maxwell came up with the theory of electromagnetism and found the connection between light and electromagnetic waves.
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G.J. Stoney came up with the idea that electricity was comprised of negative particles he called electrons.
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Sir William Crookes’ experiments with cathode-ray tubes led him to confirm that cathode-rays have a negative charge.
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Wilhelm Roentgen discovered x-rays.
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J.J. Thomson discovered the electron and proposed a model for the atom. He knew that electrons were negative, so there must be something positive. He created the 'plum pudding' model.
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Einstein found the 'photon' and came up with the 'photoelectric effect'.
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Richard Abegg found that inert gases have a “stable electron configuration.”
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Ernest Rutherford did an experiment were he shined Radium alpha particles through gold foil. He discovered the positively charged nucleus.
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He came up with the rules for how electrons move around the nucleus.
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H.G.J. Moseley discoveres that the number of protons in an element equals the element's atomic number.
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He identified 212 isotopes.
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He discovered neutrons in the nucleus.
