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Atomic Theory

By Adriana020
  • 460 BCE

    DEMOCRITUS

    All atoms are small, hard and indivisible particles made out of a single material.
  • 384 BCE

    ARISTOTELES

    Believed that the atom was divisible.

  • JOHN DALTON

    All matter was made of atoms.
    All atoms of the same element were identical.

  • J.J. THOMSON

    Inside the atom existed even smaller particles, the electrons.

  • MILLIKAN

    Confirmed that electron has a negative charge and the mass.

  • ERNEST RUTHERFORD

    Discovered the atom had a nucleus with protons.

  • HENRY MOSELEY

    Discovered each element has a positively charge in the nuclei.

  • NEILS BOHR

    Discovered electrons traveled in orbits.

  • JAMES CHADWICK

    Discovered the neutron in the atom.