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322
Aristotle
He thought that all materials on Earth were not made of atoms, but of the four elements, Earth, Fire, Water, and Air. He believed all substances were made of small amounts of these four elements of matter. https://the-history-of-the-atom.wikispaces.com/Aristotle -
400
Democritis
Father of the atom. Believed that all things consisted of indivisible units called atoms. http://www.barcodesinc.com/articles/timeline-on-atomic-structure.htm
Class Notes -
Robert Boyle
Discussed the probability of atoms existing. He proposed that elements are composed of 'corpuscles' of various types and sizes that are able to organize themselves into groups that represent different chemical substances. http://historyoftheatomictheory.weebly.com/robert-boyle.html -
Isaac Newton
Proposed a mechanical universe where small solid masses were in motion. Believed that there were pieces of that were "swimming" everywhere. http://atomictimeline.net/index.php
http://www-gap.dcs.st-and.ac.uk/~history/Mathematicians/Newton.html -
John Dalton
Developed 1st atomic theory - Billiard Ball Model. Elements consisted of atoms. All atoms of an element are identical. Atoms of each element are different from one another. Compounds consisted of atoms are different elements combined together. Chemical reactions involved the rearrangement of combinations of those atoms. http://www.barcodesinc.com/articles/timeline-on-atomic-structure.htm
Class Notes -
Gay-Lussac
Formulated the law that a gas expands lincarly with a fixed pressure and using temperature http://www.newworldencyclopedia.org/entry/Joseph_Louis_Gay-Lussac -
Michael Faraday
Studied the effect of electricity on solutions, coined term "electrolysis" as splitting of molecules with electricity. http://atomictimeline.net/index.php -
J Plucker
He built the first Cathode Ray tube. These are used to make X-Rays. http://atomictimeline.net/index.php -
Dimitri Mendelev
Periodic law. First periodic table in 1869. Discovered that the properties of elements "were periodic functions of the their atomic weights". http://atomictimeline.net/index.php
http://www.barcodesinc.com/articles/timeline-on-atomic-structure.htm -
James Clerk Maxwell
Proposed the electomanetic theory - proposed that electic and magnetic fields filled the void http://www.geog.ucsb.edu/~jeff/115a/history/jamesclarkemaxwell.html -
WIlliam Crookes
Experiments with cathode-ray tubes led him to confirm the work of earlier scientists by definitively demonstrating that cathode-rays have a negative charge. http://atomictimeline.net/index.php -
JJ Thomson
Plum Pudding model. Discovered the electron. Described atoms as ball of positive charge containing a number of electrons http://atomictimeline.net/index.php -
Marie Curie
Discovered radium and polonium and coined the radioactivity after studying the decay process of aranius and thorium http://www.barcodesinc.com/articles/timeline-on-atomic-structure.htm
http://www.staff.amu.edu.pl/~zbzw/ph/sci/msc.htm
http://atomictimeline.net/index.php -
Hantaro Nogaoka
Postulated a "Saturnia made of the atom with flat rings of electrons revolving around positively charged particle http://atomictimeline.net/index.php -
Philipp Lenard
Conducted Aluminum Foil Experiment. Found that a beam of electrons was able to pass through a sheet of aluminum foil with almost no deflection. Concluded that most of an atom's volume is just empty space. http://www.nobelprize.org/nobel_prizes/physics/laureates/1905/lenard-facts.html -
Richard Abegg
Found that inert gases have a stable electron configuration http://www.barcodesinc.com/articles/timeline-on-atomic-structure.htm
http://atomictimeline.net/index.php
http://www.chemistry.mtu.edu/~pcharles/SCIHISTORY/08nuclearatom.html -
Albert Einstein
Published the famous equation E=mc2. Created the Quantum Theory of Light - the idea that light exists as tiny particles called photons. http://atomictimeline.net/index.php
http://www.aip.org/history/einstein/ -
HGJ Mosely
Discovered that the number of protons in an element determines its atomic number http://atomictimeline.net/index.php
http://www.barcodesinc.com/articles/timeline-on-atomic-structure.htm -
Aston
Discovered the existence of isotopes through the use of a mass spectrograph. http://atomictimeline.net/index.php -
Niels Bohr
He's the Father of Quantam theory, Proposed that the atom is succesive or bital shells of electrons. Bohr came up with the "Bohr Planetary Model." http://atomictimeline.net/index.php
Class Notes -
Louis de Broglie
Discovered that electrons had a dual nature similar to both particles and waves. Particle/wave duality http://www.barcodesinc.com/articles/timeline-on-atomic-structure.htm http://www.colorado.edu/physics/2000/quantumzone/debroglie.html -
Ernest Rutherford
He is the father of nucleus physics. He developed the "gold foil experiment." Rutherford deteremined that the nucleus of an atom is very dense and has a positive charge. http://atomictimeline.net/index.php
http://www.rutherford.org.nz/ -
Ernest Schrodinger
Proposed the "Electron Cloud Theroy." Identified the electron cloud as the propable location of moving particles. http://atomictimeline.net/index.php -
Werner Heisenberg
Described atoms by means of formula connected to the frequencies of spectral lines. Proposed Principle of Indeterminancy "you can't know both the position and velocity of a particle. http://atomictimeline.net/index.php
http://www.aip.org/history/heisenberg/p01.htm -
Paul Dirac
Proposed the first theory of the existance of anti-particles http://www.barcodesinc.com/articles/timeline-on-atomic-structure.htm
http://www.magnet.fsu.edu/education/tutorials/pioneers/dirac.html -
James Chadwick
Proved the existance of the neutron. He discoverd a particle within the nucleus that has a mass similar to that of a proton. http://atomictimeline.net/index.php
Class Notes -
Ernest Lawrence
He invented the cyclotron and recognized the potential for medical isotopes. Isotopes are used to make medicines. When radioactive isotopes are introduced to the body, they give off an energy or radiation that can be tracked by imaging equipment. http://www.chemistryexplained.com/Kr-Ma/Lawrence-Ernest.html -
Glenn Seaborg
Discovered eight transuranrum elements http://atomictimeline.net/index.php
http://www.barcodesinc.com/articles/timeline-on-atomic-structure.htm
http://www.osti.gov/accomplishments/seaborg.html -
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Fredrick Saddy
Came up with the term isotope to explain the unintentianal of radioactive elements. http://atomictimeline.net/index.php -
E. Goldstein
Discovered canal rays, which have a positive charge equal to an electron. http://www.columbia.edu/itc/chemistry/chem-c2507/navbar/chemhist.html
