History of the Atomic Theory

Timeline created by NKosa
  • Period:

    Atomic Theory

  • 492

    Democritus' theory is formed

    Democritus' theory is formed
    The exact date is unknown
    Lived from 460BC - 370BC, in Abdera, Thrace
    Said everything is made of "atomos"
    Atomos means uncuttable
    He didn't do an experiment, this was philosophy
    Democritus' idea wasn't considered "true" because everyone thought Aristotle was "right" (Until Dalton)
    (492 is really 492 BC, but timetoast doen't allow BC in the date)
  • Dalton's Discovery

    Dalton's Discovery
    Born September 6, 1766, in Eaglesfield, England
    Died July 26 1844
    -all matter is made of atoms
    -atoms cannot be broken down in any way
    -all atoms of any one element are exactly the same
    Made theory after experimenting with gasses
    Was colorblind --biography.com
  • Thomson's Theory

    Thomson's Theory
    Born December 18, 1856, in Cheetham Hill, Engand
    Died Aug 30, 1940
    - Cathode Ray Experiment
    Discovered the electron
    Discovered the electron's negative charge
    "Plum Pudding Model"
    -Thomson was almost an engineer, but couldn't get the education
    (Exact date of discovery unknown)
  • Rutherford's Discovery

    Rutherford's Discovery
    Born August 30, 1871
    Died Oct 19, 1937
    Performed the Foil Experiment
    Realized that most of the mass of an atom is inside the nucleus
    Discovered the existence of the nucleus
    The neutron remained undiscovered
    During WWI, Rutherford researched antisubmarine weapons
  • Niels Bohr's Discovey

    Niels Bohr's Discovey
    Born Oct 7 1885
    Died Nov 18, 1962
    Said that electrons are in separate orbits
    Studied Rutherford's and Thomson's models to get theory
    Fun Fact: Met both Rutherford and Thomson
  • Modern

    Schrodinger developed the electron cloud
    Born Aug 12, 1887
    Died Jan 4, 1961
    Chadwick discovered the neutron
    Born Oct 20, 1891
    Died July 24, 1974