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Atomic Theory

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    Solid Sphere Model

    Solid Sphere Model
    The first atomic model created by Democritus. It's a sphere that is indivisible.
  • Antoine Lavoisier

    Antoine Lavoisier
    Lavoisier's experiments and theories helped to bring about the discussion of what an atom was and what it was made of. His early contributions led to our modern understanding of atoms with the help of numoerous indiviuals who built upon their own ideas of what the atom actually is.
  • Joseph Louis Proust

    Joseph Louis Proust
    His law of Definite Proportion contributed to the atomic model which influenced the conservation of mass which influenced the atomic theory so on and so forth until the modern atomic structural model is devolped.
  • john dalton

    john dalton
    Although two centuries old, Dalton's atomic theory remains valid in modern chemical thought. 1) All matter is made of atoms. Atoms are indivisible and indestructible. 3) Compounds are formed by a combination of two or more different kinds of atoms.4) A chemical reaction is a rearrangement of atoms.
  • Michael Faraday

    Michael Faraday
    He created two laws of electrolysis which contributed to the atomic model and atomic theory even though he was was deeply opposed to atomism.
  • J.J Thomson

    J.J Thomson
    Thomson determined that all matter is made up of tiny particles that are much smaller than atoms. He originally called these particles 'corpuscles,' although they are now called electrons. This discovery upended the prevailing theory that the atom was the smallest fundamental unit.
  • Henri Becquerel

    Henri Becquerel
    Although Becquerel did not initially comprehend what he was observing, his landmark discovery of radioactivity paved the way for a new understanding of the atom and atomic structure.
  • Marie Curie

    Marie Curie
    Building on the research of Marie Curie and others, scientists soon realized that if atoms emitted such things they could not be indivisible and unchangeable. Atoms are made up of smaller particles, and these can be rearranged.
  • Max Planck

    Max Planck
    Max Planck, a German physicist, is best known as the originator of the quantum theory of energy for which he was awarded the Nobel Prize in 1918. His work contributed significantly to the understanding of atomic and subatomic processes. Niels Bohr used Planck's theories to develop a new and more accurate model of the atom. Planck's contributions allowed for many to build from his findings.
  • Albert Einstein

    Albert Einstein
    LinkIn 1905, Albert Einstein published an analysis in which he devised a mathematical way to predict the size of both atoms and molecules. At the time, the science of atoms was still in its infancy, but Einstein's test was crucial in leading the way towards testing the reality of atoms.
  • Plum Pudding Model

    Plum Pudding Model
    Proposed by J.J Thomson this model said that the positive and negative charges were distrubted evenly throughout the atom which explained the balance.
  • Robert Milikan

    Robert Milikan
    His earliest major success was the accurate determination of the charge carried by an electron, using the elegant "falling-drop method" In addition his studies of the Brownian movements in gases put an end to all opposition to the atomic and kinetic theories of matter.
  • Ernest Rutherford

    Ernest Rutherford
    Rutherford overturned Thomson's model in 1911 with his well-known gold foil experiment in which he demonstrated that the atom has a tiny, heavy nucleus. Rutherford designed an experiment to use the alpha particles emitted by a radioactive element as probes to the unseen world of atomic structure.
  • Planetary Model

    Planetary Model
    Rutherford realized that the electrons orbit the nucleus and the closer they are the less energy they therefore have. He also started to determine that there is a specific number of electrons in each level in order to make it a stable atom. He realized that the electrons orbit the nucleus like in space.
  • Niels Bohr

    Niels Bohr
    In 1913, Niels Bohr proposed a theory for the hydrogen atom based on quantum theory that energy is transferred only in certain well defined quantities. Electrons should move around the nucleus but only in prescribed orbits. When jumping from one orbit to another with lower energy, a light quantum is emitted. Bohr's theory could explain why atoms emitted light in fixed wavelengths.
  • Louis De Broglie

    Louis De Broglie
    He was a French physicist best known for his research on quantum theory and for predicting the wave nature of electrons. His calculations answered the question as to the wave nature of electrons which allowed for further devolpment on the atomic theory.
  • Ernest Schrodinger

    Ernest Schrodinger
    A powerful model of the atom was developed by Erwin Schrödinger in 1926. Schrödinger combined the equations for the behavior of waves with the de Broglie equation to generate a mathematical model for the distribution of electrons in an atom. His contributions enabled much of how an atom behaves and much of it's charachteristics to be known.
  • Electron Cloud Model

    Electron Cloud Model
    The Electron Cloud Model was created by Erwin Schrodinger and Werner Heisnenberg. It built upon Bohr's idea that the electrons orbited around the nucleus. The elctron cloud is self explanatory and is where the electrons are present in the atom.
  • Quantum Mechanical Model

    Quantum Mechanical Model
    Created by Erwin Schrödinger the quantum mechanical model is based on mathematics. Although it is more difficult to understand than the Bohr model, it can be used to explain observations made on complex atoms.
  • James Chadwick

    James Chadwick
    In 1932, James Chadwick bombarded beryllium atoms with alpha particles. An unknown radiation was produced. Chadwick interpreted this radiation as being composed of particles with a neutral electrical charge and the approximate mass of a proton. This particle became known as the neutron, an essential part to our modern understanding of the atom.
  • Lisa Meitner

    Lisa Meitner
    Conducted experiments verifying that heavy elements capture neutrons and form unstable products which undergo fission. This process ejects more neutrons continuing the fission chain reaction.
  • Otto Hahn

     Otto Hahn
    While working with Lise Meitner and Fritz Strassman in 1939 they discovered the splitting of the atomic nucleus in Uranium and Thorium. This is more commonly known as fission. He was awarded the Nobel Prize in Chemistry in 1946. From 1939 to 1946 he continued to split atoms of other elements to see how they would arise through fission. By doing this he helped to discover the charachteristics of different atoms.
  • Glen T. Seaborg

    Glen T. Seaborg
    Appointment by President Kennedy to the Atomic Energy Commission in 1961 Seaborg worked on the structure of the atom and how it functioned. He even worked to advise the president on scientific matters regarding atomic energy. His contributions were built upon and lasting with all he did for the atom.