Atomic theory

By hi_tiara_x3
  • Oct 29, 1000

    Democritus

    Democritus
    Matter is made of small indivisable particles which have different form , position and arrangment Democritus named these Atoms.

  • John Dalton

    John Dalton
    Developed an atomic theory stating that spherical atoms had measurable properties of mass.

  • Goldstein

    Goldstein
    Used Cathode ray tubes to discover that " canal rays " have opposite properties of electrons.

  • J.J Thomson

    J.J Thomson
    Discovers the electron and used cathode ray tubes to determine the charge to mass ratio of an electron to be 1.759 x 10^8 coulombus/grams.

  • Robert Millikan

    Robert Millikan
    Performed an oil drop experiment to determine the charge and mass of an electron to be 1.603x10^-19 C and 9.11x10^-28g respectivly.

  • Ernest Rutherford

    Ernest Rutherford
    Finds that an atom has a small dense positively charged nucleus , electrons move around the nucleus.

  • Neils Bohr

    Neils Bohr
    The electron moves in a circular orbit at fixed distances from the nucleus.

  • Erwin Schrodinger

    Erwin Schrodinger
    Developos mathematical equations to describe the motion of electrons in atoms. His work leads to the electron cloud model.

  • James Chadwick

    James Chadwick
    Confirms the existance of neutrons which have no charge.Atomic nuclei contain neutrons and positivly charged protons