Atomic Theory Timeline by Patrick, victor and kamryn
400 B.C.
DEMOCRitus
Democritus was a Greek philosopher, and he was the first to hypothesize that the atom was a tiny hard sphere.
1803
John Dalton
John Dalton created the atomic theory, believed that the universe was made of tiny "uncuttable " particles and that atoms of a given element are identical.
1879
William crookes
William Crookes was the first to discover the electron.
1897
J.J. THomson
Thomson created the Plum Pudding model of the atom and discovered that the proton has a positive charge.
1908
Ernest Rutherford
Rutherford conducted the gold foil experiment and he discovered that the atom is mostly empty space.
1913
Niels bohr
He found the missing mass of the atom's nucleus and created a modle of the atom with electrons moving around the nucleus in fixed orbits.
1932
James chadwick
Chadwicks discovered neutrally charged particles, also known as the neutron.
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