Atomhistory.txt

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Author:
Tfresh13
ID:
38557
Filename:
Atomhistory.txt
Updated:
2010-09-29 21:58:47
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Chemistry Atom
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The histroy of the atom.
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  1. Dalton's Theory
    • Also known as the cannonball model it decribes:
    • -All atoms are composed of individual atoms. (True)
    • -All atoms of a given elemnt are identical. (True)
    • -Atoms of different elemnts are different. (True)
    • -Compounds are formed by the combination of different elements. (True)
    • -Atoms are solid element with no sub-atomic particles. (False)
  2. J.J. Thompon's Discovery
    • J.J. Thompson found out that:
    • -An atom contained negatively charged particles which are now known as electrons.
    • - He nick-named the design of the atom the "plum pudding model".
  3. Ernest Rutherford's Experiment
    • Ernest Rutherford, a student of Thompson's, discovered:
    • -An atom, instead of having equal concentrations of protons and electrons had one central core with a positive charge.
    • - If the existance of the nucleus is true, then most of the atom is empty space.
    • -He figured this out in the gold foil experiment.
  4. Neils Bohr
    • Neils Bohr figured out this from his studies:
    • -There was indeed a central nucleus with electrons orbiting around it.
    • -The space around the nucleus was made up of energy levels, each containing a specific number of electrons.
    • - This model was nicknamed the planetary of solar system model.
  5. Schrodinger and deBroglie
    • Schrodinger and deBroglie came up up with the wave mechanical model stating:
    • -electrons are particles that move like a wave around the nucleus.
    • -electrons move in distinct energy levels called orbitals.
    • -orbital: a region of probablilty (heisenberg) or a place an electron is likely to be found.
  6. James Chadwick
    • In 1932 Chadwick discovered:
    • -by bombarding hydrogen with beryllium found that neutral gama rays were emmited.
    • -he named these particles neutrons.
  7. Why did it take so long to discover neutrons?
    • -nuetrons have no chrage
    • -they have the same mass as a proton
    • -they reside in the nucleus with the proton
  8. The Gold Foil Experiment
    • In the gold foil experiment Ernest Rutherford:
    • -positively charged particles were shot at a thin peice of gold foil using a Cathode Ray tube.
    • -if the plum pudding model was correct the particles would have passed through because they would hit a negative elctron and go through it.
    • -many of the particles were deflected and Rutherford tracked back and realized they all were deflected off something in the middle of the atom.
    • -this meant there was a dense structure with a positive charge in the middle of the atom
  9. Neutrons
    • -no charge
    • -1 amu
    • -found in the nucleus
  10. Electron
    • -negative charge of one.
    • -found in orbitals around the nucleus.
    • -1/1836th of an amu.
    • -mass is neglible.
  11. Proton
    • -positive charge of 1
    • -1 amu
    • -found in the nucleus
  12. Amu
    Unit of mass equal to one proton/neutron or 1.67x10-24grams.
  13. Atomic Number
    number of protons (identifies elemnt)
  14. Mass number
    • -number of protons plus number of neutrons (amu).
    • -you can get it by rounding the atomic mass to the neares integer.
  15. Neutral Atoms
    number of protons equals number of electrons
  16. Finding the number of subatomic particles.
    • Protons- equal to atomic number.
    • Electrons- equal to the amount of protons in a neutral atom.
    • Neutrons- The mass number-The atomic number
    • 16- atomic number
    • 16.00- atomic mass
    • O- symbol
    • Oxygen- name

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