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Sep 23, 1500
Democritus
Developed the idea tht everything is created from atoms at around 400 B.C. He also said that atoms are indivisble and cannot be broken down. -
John Dalton
The solid sphere model was John's Dalton's explanation of the atom. It was a solid, indestructible sphere. It didn't include a nucleus or subatomic particles. -
J.J. Thomson
The plum pudding model, proposed by JJ Thomson, was seen as the atom before the discovery of the atomic nucleus. The model is composed of electrons surrounded by positive charge to balance the negative charges. -
Albert Einstein
Einstein published papers on a new method of counting and determining the size of the atoms, and on the phenomenon of Brownian motion that proved that atoms actually exist. -
Robert Millikan
Robert Millikan is credited for measuring the charge of an electron. He also accomplished the oil drop experiment, which he completed with JJ Thomson. -
Ernest Rutherford
Rutherford published his atomic theory discribing the atom as having a central nucleus surrounded by negative orbiting electrons. He found this out by doing an experiment with his gold foil model which contained a detecting screen. Created the planetary Atom model. -
Niels Bohr
Bohr proposed that electrons travel only in certain successively larger orbits. He helped develop quantum mechanics, in which electrons move from one energy level to another. -
Louis deBroglie
His theory helped explain how atoms, molecules, and protons, behave. He suggested that all matter has wave properties. -
Werner Heisenburg
German physicist who cam up with his own priciple which states that if you measure one particle the other may not be certain. -
Wolfgang Pauli
Nominated for contribution through his discovery of a new law of Nature, the exclusion principle or Pauli principle. No two electrons can hold the same 2 quatam numbers. -
Erwin Schrödinger
Formed a model off of particle waves -
James Chadwick
James discovered the neutron in the atom. -
