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Democritus found the atom and had a theory that the atom was indivisble. This was later proven wrong.
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Dalton had a theory that matter was composed of different atoms of different weights. He proposed the first atomic theory with spherical masses in motion. He had 3 points:
1. All matter consisted of tiny particles 2. Atoms are indivisble
3. Elements are categorised by the mass of the atom. -
Stoney had a theory that electricity was made of lots of negative particles, soon these particles were called electrons and are still called electrons today.
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Thomson discovered electrons and this helped people realise that atoms ARE in fact divisble and that electrons were distributed in a sea of positive charge.
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Planck is the founder of the quantum theory and is one of the most important physicists in the 20th century
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Nagaoka proposed a model which had a positively charged centre and had electrons revolving around it bound by an electrostatic force. This helps us understand how the electrons affect the nucleus and the whole atom.
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Millikan discovered the mass and charge of electrons. This led him to figuring out that the weight of an electron is 1836 times smaller than a hydrogen atom.
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Discovered the nucleus and how atoms bond together in definite proportions. Rutherford proposed that the positive charge must be localized, concentrated in a small nucleus.
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He created the Moseley Law. The law helped advance chemistry by immediately sorting the elements of the periodic table in a more logical order.
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Bohr found that electrons moved around the nucleus of the atom and that electrons move around the nucleus of the atom in restricted orbits. Bohr also found the solution to the stability of the nuclear model of the atom.
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Chadwick proved that the nucleus contain neutral particles. Chadwick proved that there were such things as neutral particles in the nucleus and they are now known as neutrons.
