Understanding of the atom

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    Origin of the atom

    Origin of the atom
    Democritus, a greek philosopher, proposed a theory that if you cut up matter into smaller and smaller pieces then eventually you will not be able to cut it any smaller. He thought that the atomos would have the same properties as the original piece. He was then set back by the widely accepted but false views of Aristotle, in 460BC.
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  • Air can push down

    Air can push down
    Evangelista Torricelli found that air could push down mercury in a tube.
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  • What is air?

    What is air?
    Daniel Bernoulli, proposed that air c is made up of tiny particles that are so small that we cannot feel or see them. He thought that they were loosly packed together.
  • Many different particles make up matter

    Many different particles make up matter
    Joseph Priestley found that he could split mercury calx stones into liquid mercury and a gas later called oxygen by heating it.
  • Conservation of Mass

    Conservation of Mass
    Antoine Lavoisier, through experiments in which he renamed hydrogen and oxygen, found that mass is not lost or gained during a chemical reaction. He also found out that hydrogen reacts with oxygen to create water.
  • Dalton's atomic theories

    Dalton's atomic theories
    John Dalton proposed that all matter is made of indivisible atoms; and that all atoms of the same element are the same, while different elements have different properties. He also proposed that chemical reactions are the combination of atoms, and that when elements react to form compounds that the compounds are of set ratios. This is called the Law of Definite Proportions.
  • Electrolysis

    Michael Faraday described the splitting of molecules with electricity as electrolysis and developed the laws of electrolysis.
    Atomic Structure Timeline
  • Planck's constant

    Planck's constant
    Max Planck used Planck's constant to explain how certain amounts of energy were omitted when the object resonates light. He used the equation: E=hv, energy omitted equals Planck's constant multiplied by the frewuency of light.
  • Plum Pie Model of the Atom

    Plum Pie Model of the Atom
    J.J. Thomson proposed his model of the atom which consisted of a round positively charged mass with negatively charged particles distributed throughout.
    History of Atomic Theory
  • E=mc^2

    Albert Einstein proposed the equation that determined the amount of energy omitted in a nuclear reaction.
  • Oil drops

    Oil drops
    R.A.Millikan's oil drop experiment helped to determine the mass and charge of an electron
  • Gold foil

    Gold foil
    Ernest Rutherford fired alpha particles at goldfoil and through this summarized that very dense, very small and positively charged.
  • Isotopes

    Aston predicted the existence of isotopes by using a mass spectrograph.
  • Bohr model of the atom

    Bohr model of the atom
    Neils Bohr proposed his model of the atom which was composed of successful electron orbits.
  • How can it be both a particle and a wave?

    How can it be both a particle and a wave?
    Joseph de Broglie held the view that all objects held both particle and wave natures. He said this was only really apparent for extremely light particles such as electrons.
  • Principle of Indeterminancy

    Principle of Indeterminancy
    Heisenberg proposed a theory that stated that the observer cannot know the position and velocity of a particle.
  • Antiparticles

    Paul Dirac proposed the existence of antiparticles. This was then confirmed for the electron and proton in 1932 and 1955 respectively
  • Schrodinger

    Schrodinger used "wave mechanics" to help to describe the atom
  • The neutron

    The neutron
    James Chadwick used beams of alpha particles to discover the other part of the nucleus
  • Nuclear Reactor

    Nuclear Reactor
    Enrico Fermi supervised the design and creation of a self sustaining chain reaction that resulted in the release of nuclear energy.