Atomic Theory Timeline

  • 400 BCE

    Democritus

    Discovered all material bodies are made up of indivisibly small atoms
  • 384 BCE

    Aristotle

    He discovered the study of formal logic
  • Lavoisier

    H discovered 33 substances, many he proposed were elements
  • Dalton

    He discovered that all matter is made of tiny indivisible particles called atoms
  • Mendeleev

    He Discovered the periodic table by the mass weight
  • Thomson

    He discovered electrons and that atoms were made up of smaller components
  • Millikan

    He discovered the magnitude of the electrons charge
  • Rutherford

    Discovered the nucleus of the atom
  • Bohr

    Discovered the atom in which the electron was able to occupy only certain orbits around the nucleus
  • Chadwick

    discovered the domain of nuclear science: he proved the existence of neutrons