Physics Atom Timeline
Category: Other
Updated: 1 Nov 2017
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Created byMarc-Anthony George
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Events
350 BC
Aristotle felt that there was no smallest
part of matter and that different substances
were made of earth, fire, air, and water.442 BC
Democritus discovered that all
matter is made up of invisible
particles called atoms.1803
John Dalton created the
Atomic Theory of Matter,
in which all matter is
made of atoms and
that atoms cannot be
created nor destroyed.1897
J.J. Thomson discovered
the electron, which led
him to create the "plum
pudding" atomic model.1909
Ernest Rutherford believed
that all the positive matter was in
the center of the atom (nucleus) ,
surrounded by electrons.1913
Neils Bohr improved Rutherford's
atomic model, with electrons
orbiting the nucleus1926
Erwin Shrodinger's new model
described how electrons move
in wave form1932
James Chadwick discovers the
neutron which helps balance
out the protons in the nucleus
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