Atomic Timeline A-8 2021-22

  • Plato
    440 BCE

    Plato

    Comes through a mathematical discovery by Empedocles, a fifth atomic type must exist which Aristotle later called "ether."
  • Democritus
    400 BCE

    Democritus

    Believed that atoms were uniformed, solid, hard incompressible and indestructible. He also thought that they moved in infinite numbers through empty space until they stopped.
  • Solar System Model
    330 BCE

    Solar System Model

    A model used to sort and order the planets.
    ( Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune )
  • Robert Boyle

    Robert Boyle

    Boyle says if the volume of a gas is decreased, the pressure increases proportionally.
  • Antoine Lavoisier

    Antoine Lavoisier

    Antoine Lavoisier found that the total mass of products and reactants in a chemical reaction are always the same.
  • The Alchemists

    The Alchemists

    They toiled countless hours over the furnace until they stumbled upon serval new substances. Also known as the elements of the periodic table.
  • The Billiard Ball Model

    The Billiard Ball Model

    John Dalton created The Billiard Ball Model because he thought atoms were the smallest particles of matter.
  • John Dalton

    John Dalton

    His atomic theory proposed that all matter was composed of atoms and indestructible building blocks.
  • Amedeo Avogadro

    Amedeo Avogadro

    Avogadro thought that equal volumes of gases at the same temperature and pressure contain equal numbers of molecules.
  • Dmitri Mendeleev

    Dmitri Mendeleev

    Dmitri found that all the known chemical elements were arranged in order if increasing atomic weight. He also is considered the "father" of the Periodic Table.
  • Robert Millikan

    Robert Millikan

    Discovered that there is a fundamental electric charge. The charge of the electron.
  • JJ Thompson

    JJ Thompson

    Experimented with cathode ray tubes. While doing so, he had shown that all atoms contain tiny negative charged, subatomic particles or electrons.
  • Plum Pudding Model

    Plum Pudding Model

    J.J Thompson made a model that explains electrons. Electrons that are surrounded by a positive.
  • Pierre and Marie Curie

    Pierre and Marie Curie

    French physicists Pierre and Marie Curie, discovered the strongly radioactive elements, Polonium and Radium.
  • Albert Einstein

    Albert Einstein

    Albert Einstein mathematically proved the existence of atoms and helped revolutionize all of the scientists through the use if statistics and probability.
  • Ernest Rutherford

    Ernest Rutherford

    Ernest Rutherford found that the atom is mostly filled with just empty space.
  • Niels Bohr

    Niels Bohr

    Niels Bohr proposed a theory of the hydrogen atom. His model explained why the atoms only emit light of fixed wavelengths.
  • Henry G.J. Moseley

    Henry G.J. Moseley

    Henry Moseley concluded that the atomic number is the number of positive charges in the atomic nucleus.
  • Erwin Schrödinger

    Erwin Schrödinger

    Erwin Schrödinger was an Austrian Physicist who took the Bohr model one step further. Schrödinger used mathematical equations to describe the likelihood of finding an electron in a certain position.
  • Electron Cloud Model

    Electron Cloud Model

    Erwin Schrödinger made a model that shows a particular area in which an electron is likely to be.
  • Werner Heisenberg

    Werner Heisenberg

    Werner Heisenberg contributed to the atomic theory through formulating quantum mechanics in terms of matrices and in discovering the uncertainty principle.
  • James Chadwick

    James Chadwick

    James Chadwick bombarded beryllium atoms with alpha particles. An unknown radiation was then produced.