Atom

Atomic Theory

By facebooker_1309792560
  • 350

    350 BCE Aristotle

    350 BCE Aristotle
    Aristotle claimed that all matter was either fire, water, earth, or air. The four qualities of those elements were dryness, hotness, wetness, and coldness. No one challenged these claims because of his reputation.
  • 400

    400 BCE Democritus

    400 BCE Democritus
    Refined Parmenides's early theory of building blocks and gave it a name, atom.
  • Period: 400 to

    Atomic Theory

  • 550

    550 BCE Parmenides

    Parmenides, an ancient Greek philosopher, comes up with the idea that everything is made up of very small building blocks

  • John Dalton's Atomic Theory

    John Dalton's Atomic Theory
    Came up with a theory of how atoms worked.
    1. all elements are composed of tiny indivisible parts called atoms
    2. atoms of same elemetn are the same
    3. atoms make compounds
    4. atoms are rearranged in chemical reactions
    the first two statements were proven false, but the last two remain true.

  • Dimitri Mendeleev devolops periodic table

    Dimitri Mendeleev devolops periodic table
    Mendeleev was a Russian chemist who developed an early form of the periodic table that was composed of the 65 discovered elements arranged by atomic weight. They were further arranged by certain physical traits and properties. Three elements were predicted and discovered within his lifetime because of his periodic table.

  • JJ Thompson

    JJ Thompson
    JJ Thompson discovered and proved the existence of the electron by his Cathode ray tube experiement.

  • Millikan

    Millikan
    Millikan was responsible for discovering the mass and charge of the electron.

  • Rutherford

    Rutherford
    Developed a model of the atom that suggested a positive nucleus with negative electrons swarming around it.

  • Niels Bohr

    Niels Bohr
    Discovered that electrons don't all just flow freely around the nucleus, they have different energy levels depending on the distance away from the center.

  • Chadwick

    Chadwick
    Chadwick discovered the neutron, the other particle in the nucleus of the atom that accounts for the other half of the mass.

  • The Manhattan Project

    The Manhattan Project
    Group of scientists doing nuclear research which resulted in the creation of the nuclear bomb.

  • Cloud Model

    Cloud Model
    Shroedinger's model that more accurately depicts the pathways of an electron. He also came up with an equation that finds out where an electron was the instant before.