History of the atom

By jessica_jacobs
  • 370

    Democritus

    Athens, Greece  He decided matter must be made up of atoms
    This was the beginning of atomic theory.

  • Newton

     England  Proposed the idea of a mechanical universe with small masses in motion.

  • Dalton

     Cumberland, England  Printed the first table of relative weights of elements. Invented atomic weight.
     First classification of atoms

  • G.J. Stoney

     Ireland  Introduced concept of electrons. Because of this, many things such as valency and conduction can be explained

  • J.J. Thomson

     England  Proposed "plum pudding Model"
    It is the basis for the current atomic model 

  • Planck

     Kiel, Germany Used the idea of quanta (discrete units of energy) to explain hot glowing matter. This helped us understand more atomic behaviour.

  • Nagaoka 

    Nagasaki, Japan  Proposed the 'Saturnian model', where an atom is compared to Saturn and its rings
     It correctly predicted that electrons orbit the nucleus

  • Millikan

     Illinois  Discovered the charge and mass of electrons
    More of an understanding of atomic behaviour

  • E. Rutherford

     Essex, England  Proposed the 'Rutherford model' where there is a small positive nucleus and negative electrons orbiting
     Scientists realise that atoms are made up of sub-atomic particles

  • H.G.J. Moseley

    England  Rearranged the Periodic table so it was arranged by atomic number not atomic weight. Made accurate predictions on missing elements

  • Bohr

     Copenhagen, Denmark  Proposed 'Bohr model' where the electrons are arranged in shells
    This is the current atomic model

  • James Chadwick

    England Discovered the neutron