Atomic Timeline

  • Plato
    427 BCE

    Plato

    Plato theorized that solid forms of matter are composed of invisible elements shaped like triangles.
  • Democritus
    400 BCE

    Democritus

    Democritus theorized that atoms where specific to the material they composed.
  • Robert Boyle

    Robert Boyle

    Robert discovered that the volume of gas is inversely proportional to its pressure.
  • The Alchemists

    The Alchemists

    The Alchemists believed that all metals were formed from 2 principles. Mercury and sulfur.
  • Antone Lavoisier

    Antone Lavoisier

    Antone defined the laws of conservation of mass/ discovered mass is neither created or destroyed in chemical reactions.
  • Billiard Ball Model

    Billiard Ball Model

    Created in the early 1800 by John Dalton.
  • John Dalton

    John Dalton

    Johns atomic theory was that all matter was made up of indestructible / invisible atoms.
  • Amedeo Avogadro

    Amedeo Avogadro

    Avogadro discovered equal volumes of gas contain equal numbers of molecules.
  • Dmitri Mendeleev

    Dmitri Mendeleev

    Dmitri invented the periodic table.
  • JJ Thompson

    JJ Thompson

    JJ discovered the electron.
  • Pierre and Marie Currie

    Pierre and Marie Currie

    They discovered radioactive elements such as radium.
  • Plum Pudding Model

    Plum Pudding Model

    Created by Thomas Thomson In 1904.
  • Albert Einstein

    Albert Einstein

    Albert mathematically proved the existence of atoms.
  • Robert Millikan

    Robert Millikan

    Robert discovered the accurate determination of the charge carried by an electron.
  • Ernest Rutherford

    Ernest Rutherford

    Ernest established that most of the weight of atoms is concentrated in the nucleus.
  • Henry G.J Mosely

    Henry G.J Mosely

    Henry discovered positive charge in the nucleus of an atom/atomic number.
  • Neils Bohr

    Neils Bohr

    Neils proposed a model of the atom in which the electron was able to occupy only certain orbits around the nucleus.
  • Solar System Model

    Solar System Model

    Created in 1913 by Neils Bohr.
  • Electron Cloud Model

    Electron Cloud Model

    Created by Erin Schrödinger in 1926 and by Werner Heinsberg.
  • James Chadwick

    James Chadwick

    James discovered the neutron.