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Jan 1, 1000
Democritus, Greece (1000BC)
Proposed that all matter is made of almost infinite indivisible particles which differ from each other in form, position, and arrangement
http://particleadventure.org/other/history/earlyt.html -
Isaac Newton, England
Proposed a mechanical universe with small solid masses in motion.
http://www.newton.ac.uk/newtlife.html -
John Dalton, England
Explained the relative weights of atoms, what atoms are, general things on atoms; devised the modern atomic theory
http://en.wikipedia.org/wiki/John_Dalton -
George Johnstone Stoney, Ireland
Proposed that electricity was made of negative particles called electrons; introduced us to the basic concept of negative charge
http://en.wikipedia.org/wiki/George_Johnstone_Stoney -
Joseph John Thomson, America
Discovered the electron in a series of experiments designed to study the nature of electric discharge and proposed a model of the atom; developed Stoney’s theory of negative charge and created a more in-depth definition -
Max Planck, Germany
Founded the Quantum mechanical theory; helps us understand Quantam physics
http://en.wikipedia.org/wiki/Max_Planck -
Hantara Nagaoka, Japan
Created a “planetary” model for an atom, based on the solar system analogy; helps us understand the structure of the atom, and later helped Rutherford and Bohr
http://www.answers.com/topic/hantaro-nagaoka -
Robert Andrews Millikan, America
Measured the charge of an electron by using oil drops; confirmed J.J. Thomson’s theory and paved the way for further investigations http://www.barringtonhighschool.org/Chemistry_Web/Chem%20history/Millikan/milikan.htm -
Ernest Rutherford, New Zealand
Postulated that atoms have their positive charge concentrated in a very small nucleus and thereby pioneered the Rutherford model of the atom; gives us an understanding of the structure of the atom
http://en.wikipedia.org/wiki/Ernest_Rutherford -
Henry Gwyn-Jeffreys Mosely, England
Sorted elements out by their atomic numbers or number of protons; established the scientific basis of the Periodic Table by arranging chemical elements in the order of their atomic numbers
http://www.chemistryexplained.com/Ma-Na/Moseley-Henry.html -
Niels Bohr, Denmark
Won the Nobel prize in physics for his “work on the structure of atoms”. He worked out and presented the structure of atoms; his pictures still serve as an elucidation of physical and chemical properties of elements. http://nobelprize.org/nobel_prizes/physics/laureates/1922/bohr-bio.html -
James Chadwick, England
Proved the existence of neutrons and subsequently won the Nobel Prize in 1935; proves the form of atoms
http://nobelprize.org/nobel_prizes/physics/laureates/1935/chadwick-bio.html