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John Dalton
Dalton was the originator of what is now called the Atomic Theory. He was one of the first scientists to find the link between elements and atoms, and how atoms differed from each other. Dalton proposed that the atom was the smallest particle of matter, and that atoms could not be created or destroyed. http://cstl-csm.semo.edu/cwmcgowan/ch181/atomhist.htm
Big Ideas- Science Textbook -
Marie Curie
Marie Curie was a Polish born French chemist. She worked with her husband Pierre Curie and together and in 1901 they discovered two radioactive elements, polonium and radium. She also discovered that you can measure the strength of radiation by using uranium. http://en.wikipedia.org/wiki/Marie_Curie http://www.chemheritage.org/discover/online-resources/chemistry-in-history/themes/atomic-and-nuclear-structure/curie.aspx -
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. Thomson put forward the "plum pudding" model of the atom. This model showed the volume of the atom and is composed primarily of the more larger positive portion (the plum pudding). The smaller electrons, or ‘raisins’ in the plum pudding, are dispersed throughout the positive mass to maintain charge neutrality. cstl-csm.semo.edu
www.chemheritage.com -
Ernest Ruhterford
In 1911, Ernst Rutherford proposed that all of the positive charge and all of the mass of the atom occupied a small volume at the center of the atom and that most of the volume of the atom was empty space occupied by the electrons. This was a result to the gold-foil experiment he conducted. http://www.britannica.com
http://cstl-csm.semo.edu/cwmcgowan/ch181/atomhist.htm -
Henry Mosely
In 1913, Henry Moseley put forward the idea that the relationship between the energy of x-rays emitted by the elements increased in a linear fashion with each successive element in the periodic table was a function of the positive charge on the nucleus. This rearranged the periodic table by using the atomic number instead of atomic mass to represent the progression of the elements. http://mrcauseysworld.com/chemistry/atomic_number.html
http://cstl-csm.semo.edu/cwmcgowan/ch181/atomhist.htm -
Francis Aston
1919 was the year that Francis Aston invented the mass spectrograph and the first person to observe isotopes. For example he observed that there were three different kinds of hydrogen atoms. While most of the atoms had a mass number of 1 he also observed hydrogen atoms with mass numbers of 2 and 3. Modern atomic masses are based on mass spectral analysis. Continuing his work, he led Rutherford to predict the existence of the neutron. http://www.nuclearfiles.org
http://www.britannica.com -
Niels Bohr
Niels Bohr contribution to atomic theory was the atomic model. He was the first to discover that electrons travel in different orbits. He also figured out that the electrons in the outer orbit determines the properties of the element. The element bohrium was named after him and in 1922 he won a nobel prize for his work. http://www.livescience.com/32016-niels-bohr-atomic-theory.html
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Erwin Schrodinger
Erwin Schrödinger is an Austrian physicist. In 1926 he took the atom model of Niels Bohr another step further. He used equations to find the probability of finding an electron in a certain position. This model is known as the quantum mechanical model. In 1933, he won the Nobel Award in Physics. https://www.shodor.org/chemviz/overview/schroeq.html
http://www.nobelprize.org/nobel_prizes/physics/laureates/1933/schrodinger-facts.html
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Murray Gell-Mann
Murray Gell-Mann has had a very large contribution to the atom. He discovered the 'quark' which makes the up protons and neutrons. He was born on September 15th in 1929, he is still alive and currently living in Santa Fe, New Mexico. In 1969, he won the Nobal Prize of Physis for discovering the quark. http://en.wikipedia.org/wiki/Murray_Gell-Mann
http://www.nobelprize.org/nobel_prizes/physics/laureates/1969/gell-mann-bio.html -
James Chadwick
James Chadwick had a very large contribution to atomic theory. In 1932, he proved, just like he predicted that there is a neutron. He also found that the atomic number is the number of protons in an atom. In 1935, he won the Nobel Prize in Physics award. http://en.wikipedia.org/wiki/James_Chadwick
http://jameschadwickatomictheory.weebly.com/
http://jameschadwickatomictheory.weebly.com/
