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Atomic Timeline Mason

  • Plato
    440 BCE

    Plato

    Theorizes atoms are composed of indivisible elements shaped like triangles.
  • Democritus
    400 BCE

    Democritus

    Believed atoms were solid, hard and incompressible and moved throughout space
  • Solar System Model
    1543

    Solar System Model

    Created by Nicolaus Copernicus in 1543, he corrected past theories stating the sun is the center of our solar system.
  • Robert Boyle

    Robert Boyle

    Believed everything was made of very tiny particles known as atoms.
  • Antone Lavoisier

    Antone Lavoisier

    Grounded the law of conservation of mass explaining how matter was conserved.
  • Biliard Ball Model

    Biliard Ball Model

    Created by John Dalton in the early 1800s, he thought atoms were small, hard spheres with no internal parts.
  • John Dalton

    John Dalton

    Stated that all matter is made of atoms, which are indivisible.
  • Amadeo Avogadro

    Amadeo Avogadro

    States equal volumes of gases at the same temperature and pressure contains same number of particles
  • Dmitri Mendeleev

    Dmitri Mendeleev

    States that elements are arranged according to atomic weights.
  • JJ Thompson

    JJ Thompson

    Says all atoms contain negatively charged subatomic particles, or electrons
  • Pierre and Marie Curie

    Pierre and Marie Curie

    Suggested that rays that gave off polonium and radium were particles from tiny atoms
  • Plum Pudding Model

    Plum Pudding Model

    Created by J.J. Thomson in 1904, it shows his discovery of the electron.
  • Albert Einstein

    Albert Einstein

    States that any liquid is made up of molecules.
  • Robert Millikan

    Robert Millikan

    Millikan made the discovery that all electrons carry the same amount of negative charge.
  • Ernest Rutherford

    Ernest Rutherford

    Described atoms as having a tiny dense and positively charged core called the nucleus.
  • Neils Bohr

    Neils Bohr

    Proposed a theory for the hydrogen atom based on quantum theory that states physical quantities take discrete values
  • Henry G. J. Mosely

    Henry G. J. Mosely

    stated that the frequencies are proportional to the squares of whole numbers that are equal to the atomic number plus a constant.
  • Erwin Schrodinger

    Erwin Schrodinger

    Believes the behavior of electrons in atoms could be explained mathematically.
  • Electron Cloud Model

    Electron Cloud Model

    Erwin Schrodinger created this model in 1926. It consisted of a dense nucleus surrounded by a cloud of electrons at various levels in orbitals.
  • James Chadwich

    James Chadwich

    Proved the existence of neutrons.
  • The Alchemists

    The Alchemists

    Believed all metals were formed from mercury and sulfur.