Atoms timeline picture

Atomic Model Timeline

By Roslar
  • 100

    Democritus

    Democritus
    Abdera, Thrace, Greece. 460B.C.E-370B.C.E
    Many discoveries linked with his mentor, Leucippus
    Theory:
    - everything is made of atoms
    - between atoms, there lies empty space
    - sdolidness of material determines atom's shape -http://en.wikipedia.org/wiki/Democritus

  • John Dalton

    John Dalton
    England, 1760-1844
    Atomic Theory:
    - Elements are made of extremely small particles called atoms
    - atoms of a given element are identical in size, mass, and other properties; atoms of different elements differ in size, mass, and other properties.
    - Atoms cannot be subdivided, created, or destroyed.
    - Atoms of different elements combine in simple whole number ratios to form chemical compounds -http://en.wikipedia.org/wiki/John_Dalton

  • Joseph Thomson

    Joseph Thomson
    England, 1856-1940
    - Discovered electrons by experimenting with cathode rays.
    Atomic model:
    - A sphere of positive charge with electrons in it. -http://en.wikipedia.org/wiki/J._J._Thomson

  • Ernest Rutherford

    Ernest Rutherford
    New Zealand, 1871-1937
    - Theorized a small, positively charged nucleus, and later discovered protons.
    - experimented with radeoactivity to discover alpha rays and beta rays.
    - discovered radeoactive decay and half-lives.
    Atomic Model:
    - A nucleus made of protons, orbited by electrons. -http://en.wikipedia.org/wiki/Ernest_Rutherford

  • Niels Bohr

    Niels Bohr
    Denmark, 1885-1962
    - proposed that there are energy levels of electrons.
    - electrons orbit at a fixed distance from the nucleus, but can jump to a different level. -http://en.wikipedia.org/wiki/Niels_Bohr

  • Werner Heisenberg/Erwin Schrodinger

    Werner Heisenberg/Erwin Schrodinger
    German, 1901-1976.
    Austrian, 1887-1961.
    - developed quantum theory and quantum mechanics.
    Atomic Model:
    - A positively charged nucleus made of protons and neutrons, with electron orbitals dictating where an electron may be at any point in time. -http://en.wikipedia.org/wiki/Werner_Heisenberg
    -http://en.wikipedia.org/wiki/Erwin_Schr%C3%B6dinger

  • James Chadwick

    James Chadwick
    United Kingdom, 1891-1974.
    - head scientist of the Manhattan Project.
    - discovered the neutron
    Atomic Model:
    - electrons orbit a nucleus made of protons and neutrons. -http://en.wikipedia.org/wiki/James_Chadwick