Katie Haines - The Atomic Model

Timeline created by khain
  • Aug 1, 1000

    Democritus

    Democritus
    Democritus believed everything was made of extremely small particals that could not be divided. He called them atoms, from a greek word meaning uncut oor invisable. He thougt there were different types of atoms with specific properties. This was done through discussion. (500B.C.)
  • Oct 27, 1000

    Aristotal

    Aristotal
    (500 B.C.)
    He didn't think there was a limit of times that matter could be divided. He used a model showing all substances built up from four elements - earth, air, fire, and water, and all the elements were a combo of cold, wet, dry, hot.
  • John Dalton

    John Dalton
    Dalton's Theory
    -All elements are composed of atoms
    -All atoms of the same elements have the same masses, and atoms of different elements have different masses
    -Compounds contain atoms of more than one element
    -In a particular compound, atoms of different elements always combine in the same way To prove his theory,he made wooden spheres to represent the elements. Each type of atom is represented by a tiny solid spere with a different mass.
  • J.J. Thomson

    J.J. Thomson
    He pictured electrons embedded in a sphere of positive electric charge. He used an electric current to learn more about atoms.
  • Hantaro Nagoka

    Hantaro Nagoka
    Nagoka suggests that an atom has a centeral nucleus, and that electrons move in orbit, like the rings around Saturn.
  • Ernest Marsden

    Ernest Marsden
    Marsden was on of Rutherford's students, he asked him to find out what happens to alpha particals when they pass through a thin sheet of gold. He used the method seen in the diagram to the left.
  • Ernest Rutherford

    Ernest Rutherford
    He believed an atom has a dense, positivley charged nucleus. Electrons move randomly in the space around the nucleus.
  • Louis de Brogile

    Louis de Brogile
    He proposes that moving particals, like electrons, have some properties of waves. Within a few years, evidece is collected to support his idea.
  • Erwin Schrodinger

    Erwin Schrodinger
    Schrodinger developes mathmatical equations to describe the motions of electrons in atoms. His work leads to the deveelopment of the electron cloud model.
  • James Chadwick

    James Chadwick
    Chadwick confirms the exsistance of neutrons, which have no charge. Atoms nuclei contain neutrons and positivley charged protons.
  • Glen Seaborg

    Glen Seaborg
    He synthesized six transurnium elements and suggests a change in the periodic table.
  • Enrico Fermi

    Enrico Fermi
    He conducted the first controlled chain reaction releasing enegy from the atoms nucleus. He recieved a Nobel Prize in 1938.