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Democritis
A Greek plilosopher originated the though that matter is composed of invisible elements -
Period: to
Epic Atomic Theory
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John Dalton
John developed a theory that all matter is composed of different atoms of different weights and is combined in ratios by weight. He also said atoms are spherical and in motion. -
Pierre and Marie Currie
Theorized that radioactive particles cause atoms to break down -
JJ Thompson
JJ discovered electrons using properties of cathode rays -
Max Planck
Stated that electromagnetic energy could only be emitted in quantized form. (His quanta is now called photons) -
Hantaro Nagaoka
Suggests that the atom has acentral nucleus -
Robert Milikan
Robert measured the charge of a single electron -
Ernest Rutherford
Developed a theory for the structure of an atom, he used a gold foil experiment to help him look at the scattering of alhpa particles, he was the first to demonstrate the atomic nucleus existence -
Neils Bohr
Neil developed the Bohr atomic model which stated that electrons are trveling in orbit around the nucleus -
Luis De Brogive
Proposes that moving particles like electrons, have some properties of waves -
Erwin Shrodinger
He described how electrons move in a wave form -
Heisenberg
described atoms by means of formula connected to frequencies of spectrical lines -
Paul Dirac
Proposed Anti-particles -
James Chadwick
Discovers the nuetron component of the atomic nucleus -
Mann
Processes the Quark model and describes elementary particles that have no substructure