Small spherical solid indivisible model

atomic model time line

By gjimenez199
  • 460

    Democritus

    Democritus
    Democritus asked himself that if he breaks a piece of matter in half, then breaks it in half again, how many more breaks can he make before he could no longer break it. He theorized that the smallest piece of matter is called an atom, a tiny, invsible particle.

  • John Dalton

    John Dalton
    Dalton Laws:
    Law of Conservation of Mass- Mass is neither created nor destroyed in a chemical reaction
    Law of Constant Composition- A given compound always contains the same elements in the same proportions by mass
    Atomic Theory of Matter:
    -each element is composed of atoms
    -all atoms are specific to the element
    -conservation of mass
    -a given compound always has the same relative numbers and kinds of atoms

  • Dobereiner

    Dobereiner
    discovered trends in certain properties of selected groups of elements

  • J.A.R. Newlands

    J.A.R. Newlands
    Law od Octaves : "any given element will exhibit analogues behaviour to the eighth element following it in the table"

  • Dmitri Mendeleev

    Dmitri Mendeleev
    Periodic Law:
    arranged elements in 7 groups by their similar properties ("periodic functions of their atomic weights")

  • Lothar Meyer

    Lothar Meyer
    published table that releated atomic number and atomic volume

  • JJ Thomson

    JJ Thomson
    Discovered electrons using Cathode Ray Tubes
    electron charge -1.6021773 x 10^-19 C
    electron mass 9.109390 x 10^31 kg

  • Ernest Rutherford

    Ernest Rutherford
    discovered alpha and beta rays

  • Max Planck

    Max Planck
    used the idea of quanta to explain hot glowing matter

  • Albert Einstein

    Albert Einstein
    E=mc^2
    Energy=mass x speed of light squared

  • Hans Geiger

    Hans Geiger
    created a device that would detect alpha particles

  • electron cloud

    electron cloud
    the positive charge and the mass of an atom is concentrated towards the center of an atom and that the electrons orbit around the atomic center

  • Ernest Rutherford

    Ernest Rutherford
    discovered that the nucleas was very dense, small, and had a positive charge using fold foil experiment

  • Neils Bohr

    Neils Bohr
    created atomic model that depicted orbital electron shells

  • James Chadwick

    James Chadwick
    discovered neutron

  • cleaning up and oil spill

    cleaning up and oil spill
    LA Times- scientists begin discovering new more efficient ways to clean up oil spills. Research was sparked after 1989 oil spill in Alaska.