atomic theory timeline

By maddieperkins
  • 400

    Democritus

    Democritus
    Nationality (unkown?)
    first discover of the atomic theory
    1.All matter consists of invisible particles called atoms.
    2. Atoms are indestructible.
    3. Atoms are solid but invisible.
    4. Atoms are homogenous.
    5. Atoms differ in size, shape, mass, position, and arrangement.
    ->Solids are made of small, pointy atoms.
    ->Liquids are made of large, round atoms.
    ->Oils are made of very fine, small atoms that can easily slip past each other.
  • 465

    leucippus

    His mentor, Leucippus, originally came up with the atomic theory, but it was then adopted by Democritus. The atomic theory stated that “The universe is composed of two elements: the atoms and the void in which they exist and move.” According to Democritus atoms were miniscule quantities of matter. Democritus hypothesized that atoms cannot be destroyed, differ in size, shape and temperature, are always moving, and are invisible. He believed that there are an infinite number of atoms.

  • John Dalton

    John Dalton
    Nationalty- Brittish/English
    Recognised that each compound is always made of the same elements combined in the same unique proprtions by mass.
    - all matter is composed of atoms.
    - atoms are the same size
    - atoms cannot be destroyed
    Dalton believed the atom was an invisible solid core surrounded by envelope of heat.

  • Philip Lenard

    Nationality- German

  • JJ thomson

    JJ thomson
    Nationality- Brittish
    Thomson realized that atoms had to be neutral or you would get shocked everytime you touch matter.

  • Ernest Rutherford

    Ernest Rutherford
    Nationality- Brittish
    Rutherford shot alpha particles through gold foil and most went right and a few bounced back. He proved that there is quite a bit of space in atoms. He also proved that there must be a tiny positively charged region in the atom.

  • Niels Bohr

    Niels Bohr
    nationality - Danish
    Bohr recognized that atoms give off specific color of light when heated. He suspected the light emission was caused by electrons. Bohr also discovered that electrons can jump to higher energy levels when heated.
    His model- bohrs model is also called the planetary medel evevetually became the quantium model

  • James Chadwick

    nationality- English
    Discovery of the Nuetron in 1932 cannot find exact date of discovery.