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John Dalton
John Dalton's theory was based on the premise that the atoms of different elements could be distinguished by differences in their weights. He stated his theory in a lecture to the Royal Institution in 1803. The theory proposed a number of basic ideas.
Resouces: 'Atomic theory proposed by John Dalton'
http://www.rsc.org/chemsoc/timeline/
Date accessed: 12th of Septemeber 2013
'Atomic Theory'
http://www.iun.edu/~cpanhd/C101webnotes/composition/dalton.
Date accessed: 12th of Septemeber 2013 -
Marie Curie
Maria Curie was one of the first woman scientists to win worldwide fame, and indeed, one of the great scientists of this century. She had degrees in mathematics and physics. Marie Curie performed pioneering studies with radium and polonium and contributed profoundly to the understanding of radioactivity.
Resources: 'Marie Curie's Discovery'
http://www.nobelprize.org/nobel_prizes/themes/phy
'Atomic Structure Timeline'
http://atomictimeline.net/index.php
Date accessed: 13th of September 2013 -
Ernest Rutherford
In 1899 Ernest Rutherford was responsible for a remarkable series of discoveries in the fields of radioactivity and nuclear physics. He discovered alpha and beta rays, set forth the laws of radioactive decay, and identified alpha particles as helium nuclei. Most important, he postulated the nuclear structure of the atom.
Resources: 'Ernest Rutherford biography'
http://www.rsc.org/chemsoc/timeline/pages/1911.html
'Ernest Rutherford '
http://www.nzedge.com
Date accessed: 12th of Septemember 2013 -
J.J Thomson
In 1904 Thomson suggested a model of the atom as a sphere of positive matter in which electrons are positioned by electrostatic forces. His efforts to estimate the number of electrons in an atom from measurements of the scattering of light, X, beta, and gamma rays.
Resources: 'J.J Thomson'
http://www.biography.com/people/jj-thomson-40039
'J.J. Thomson - Biographical'
http://www.nobelprize.org/nobel_prizes/physics/laureates/1906/thomson-bio.html
Date acessed: 12th of September -
Henry Moseley
Henry Moseley was an English physicist who demonstrated that the major properties of an element are determined by the atomic number and he firmly established the relationship between atomic number and the charge of the atomic nucleus. This research occurred in the year of 1913.
Resources: 'Henry Moseley'
http://www.famousscientists.org/henry-moseley/
Date accessed 12th of September 2013
Who was Herny Moseley?
http://www.chemistry.co.nz/henry_moseley.htm
Date accessed 12th of September 2013 -
Niels Bohr
Niels Bohr applies quantum theory to Rutherford's atomic structure by assuming that electrons travel in stationary orbits defined by their angular momentum. This led to the calculation of possible energy levels for these orbits. These events occurred in 1915.
Resources: 'Bohr-Atomic Model'
http://www.rsc.org/chemsoc/timeline/pages/1913.html
'The Nobel Prize in Physics 1922'
http://www.nobelprize.org/nobel_prizes/physics/laureates/1922/
Date accessed: 12th of September -
Francis Aston
In the year 1919, Francis Aston made his most significant contribution to atomic science with the invention of the mass spectrograph. The invention prompted him to devise his famous Whole Number Rule. The rule of which became crucial to future developments in nuclear energy technology.
Resources: 'Francis William Aston'
http://www.nuclearfiles.org/menu/library/biographies/bio_aston-francis.htm
'Francis W. Aston'
http://www.nndb.com/people/289/0000999
Date accessed: 12th of Septemeber 2013 -
Erwin Schrödinger
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.
Resources: 'Erwin Schrödinger'
http://chemed.chem.purdue.edu/genchem/history/schrodinger.htm
Date accessed 12th of September 2013
'Nobel Prize'
http://www.nobelprize.org/nobel_prizes/physics/laureates/1933/
Date accessed: 12th of September 2013 -
James Chadwick
James Chadwick made a fundamental discovery in the doorman of nuclear science. James proved the existence of neutrons and he established that atomic number is determined by the numbers of protons in an atom. He also discovered the neutron. James was most famous for his discovery of the neutron in an atom.
Resources: 'Atomic Structure Timeline'
http://atomictimeline.net/index.php
'A Timeline on Atomic Structure'
http://www.barcodesinc.com/articles/timeline
Date accessed: 13th of September 2013 -
Murray Gell-Mann
American theoretical physicist Murray Gell-Mann developed the concept of strangeness for particles in 1953, explaining with a quantum number why some hadrons decay rapidly by the strong nuclear force while others decay more slowly by the weak force, contrary to previous theories.
Resources: 'Murray Gell-Mann'
http://www.nndb.com/people/310/000023241/
'Murray Gell-Mann - Biographical'
http://www.nobelprize.org/nobel_prizes/physics/laureates/1969/gell-mann-bio
Date accessed: 12th of September 2013
