History of the Atom

Satisfactory Essays
Jo Adrian P. del Mundo CN 08
3S (A) August 1, 2013
Atomic Models
The Electron Cloud Model
- an atom is comprised of a nucleus made up of neutrons and protons, and electrons moving extremely fast around the nucleus, forming an electron cloud instead of moving in orbits like what Bohr’s model suggests
- proposed by Erwin Schrodinger in 1926, when he derived this model using a mathematical equation that he himself made http://1.bp.blogspot.com/-LEqGPr4h8R4/TsgJyT6vP6I/AAAAAAAAAKE/pTl6O3V2u0M/s200/electron_cloud_model.jpg The Planetary/Bohr’s Model
- an atom is comprised of a nucleus made up of neutrons with a neutral charge and protons with a positive charge, with electrons going around the atom in energy levels, similar to the solar system
- proposed by Neils Bohr in 1922 when he applied knowledge regarding energy levels of electrons which was not available during Rutherford’s time http://mrskingsbioweb.com/images/image66.gif The Nuclear Model
- an atom is made up of electrons near its edge and a nucleus which has a positive charge
- proposed by Ernest Rutherford in 1911 when he saw a few Alpha particles bouncing off in different directions instead of going straight through the gold foil like the others http://upload.wikimedia.org/wikipedia/commons/7/7d/Rutherfordsches_Atommodell.png The Plum Pudding Model
- an atom is a positively charged substance with electrons scattered around inside it
- proposed by JJ Thomson in 1904 when he saw how electric current went through gas and was attracted towards the negative plate in a cathode ray tube http://www.nobelprize.org/educational/physics/quantised_world/structure-images/fig2b.gif The Billiard Ball model.
- an atom is round, hard, and had no smaller parts.
- proposed by John Dalton in 1803, when he discovered that gases can only be combined using specific proportions

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