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Period: 401 BCE to
Atomic Timeline
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400 BCE
Democritus discovery
He invented the very idea of an atom and started changing thinking on things are made up. -
390 BCE
World event within 10 years of Democritus
The Gauls almost destroy a new, young Roman Empire and were forced to pay a large ransom to get their city back wich almost ended the empire before it even got to full form -
John Dalton and the "Marble" model
He defined an atom to be a ball structure, as the concepts of atomic nucleus and electrons were unknown at the time. At the time an atom would just be drawn as a circle -
World event within 10 years of John Dalton
The war of 1812 is still ongoing between the British and Americans with a lot of battling in the mid-northern US -
Michael Faraday discovery
Faraday made one of his greatest discoveries - electromagnetic induction: the "induction" or generation of electricity in a wire utilizing the electromagnetic effect of a current in another wire. The induction ring was the first electric transformer. -
Eugen Goldstein
In 1886 he discovered what he termed Kanalstrahlen, or canal rays, also called positive rays; these are positively charged ions that are accelerated toward and through a perforated cathode in an evacuated tube. -
JJ Thompson "Plum pudding" Model
Thompson's "Plum Pudding" model demonstrates that an atom is made of electrons spread out through a spherical cloud of positive charge. -
Robert Millikan
Robert Millikan succeeded in precisely determining the magnitude of the electron's charge. Small electrically charged drops of oil were suspended between two metal plates where they were subjected to the downward force of gravity and the upward attraction of an electrical field. -
Ernest Rutherford "Nuclear Model"
The atom is mostly empty space but has a nucleus in the middle -
Within 10 years of Thomson discovery
In 1912 World war 1 begins -
Neils Bohr "Solar system" model
electrons move around the nucleus; electrons cannot occupy energy values between the fixed energy levels. -
10 years after Bohr discovery
League of Nations formed -
Edwin Schroedinger “electron cloud” model
electrons do not move in set ways around the nucleus but they move in waves, it is impossible to know where electrons are but we have clouds of probability -
World event within 10 years of Shroedinger discovery
United states stock market crashes -
Werner Heisenberg
Werner Heisenberg contributed to atomic theory through formulating quantum mechanics in terms of matrices and in discovering the uncertainty principle, which states that a particle's position and momentum cannot both be known exactly. -
James Chadwick “electron cloud” model with neutrons added
proved the existence of neutrons, elementary particles void of any electric charge -
World Event within 10 years of Chadwick’s discovery
The invasion of Poland by Germany takes place and World War 2 begins