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Atomic Theory

By aleckher
  • 460 BCE

    Democritus

    Democritus
    Proposed that atoms are indivisible.
  • 384 BCE

    Aristoteles

    Aristoteles
    Denied the existence of atoms. Elements are indivisible substances.

  • John Dalton

    John Dalton
    Atoms of a same element are identical.

  • J.J. Thomson

    J.J. Thomson
    Proved that atoms are divisible

  • Millikan

    Determines electrons have negative charge and are present in all atoms

  • Ernest Rutherford

    Ernest Rutherford
    New model, nucleus is a positive region with electrons orbiting around it.

  • Henry Moseley

    Atomic number = # of protons

  • Niels Bohr

    Niels Bohr
    Electrons orbit around the nucleus in different levels

  • Erwin Schrodinger

    Erwin Schrodinger
    Electrons travel the nucleus as a cloud

  • James Chadwick

    James Chadwick
    Neutron is a particle found in the nucleus, it has no charge