the History of Atomic Theory

By Dylan_Brumbalow
  • 500

    Democritus

    Democritus
    Democritus (460 – 370 B.C.)
    First person to suggest that matter could not be infinitely divided.
    “Atoms can not be created, destroyed, or further divided”
  • 550

    Aristotle

    Aristotle
    Aristotle (384 – 322 B.C.)
    Disagreed with Democritus’ idea that atoms move through empty space.

  • John Dalton

    John Dalton
    John Dalton (1766 – 1844)
    English schoolteacher who marks the beginning of the development of modern atomic theory.

  • J.J. Thompson

    J.J. Thompson
    Physicist J.J. Thompson (1856 – 1940) designed a series of CRT experiments at Cambridge to determine the ratio of the particle’s charge to its mass.

  • Robert Millikan

    Robert Millikan
    American Physicist Robert Millikan (1868 – 1953) designed an oil drop apparatus to determine the charge of the electron.
    Determined that the magnitude of the charge of the electron was 1.602x10-19 coulombs.

  • Ernest Rutherford

    Ernest Rutherford
    Ernest Rutherford (1871 – 1937) studied how positively charged α-particles interacted with solid matter. He designed an experiment to see if α-particles would be deflected as they passed through a thin sheet of gold foil.

  • James Chadwick

    James Chadwick
    English physicist, James Chadwick (1891 – 1974) demonstrated that the nucleus had another neutral subatomic particle, the neutron