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Antoine Lavoisier
Lavoisier discovered that matter is conserved in a chemical reaction. He discovered the Law of Conservation of Matter. This discovery shows that the atoms are not created or destroyed in chemical reactions. (http://chemed.chem.purdue.edu/genchem/history/lavoisier.html) -
Joseph Louis Proust
Joseph Louis Proust discovered the Law of Definite Proportions. This law proves that all pure chemical compunds made up of elements in defined proportions. (http://historyoftheatomictheory.weebly.com/joseph-proust.html)
(http://science.howstuffworks.com/dictionary/famous-scientists/chemists/joseph-louis-proust-info.htm) -
Solid Sphere Model
The solid sphere model was the first atomic model. This model was proposed by John Dalton. He claimed that the atom could not be split into smallter parts and that it was a solid sphere. (http://thehistoryoftheatomicmodel.weebly.com/the-solid-sphere-model.html) (http://thehistoryoftheatom.weebly.com/john-dalton.html) -
John Dalton
John Dalton came up with an atomic theory that had four parts. He proposed that all matter was made up of atoms, that all atoms have the same mass and properties, that two or more atoms combined form compounds,and that chemical reactions are rearangement of atoms. (http://www.iun.edu/~cpanhd/C101webnotes/composition/dalton.html) (http://atomictimeline.net/index.php) -
Michael Faraday
Michael Faraday discovered the idea that atoms had an electrical unit. His discovery showed that electrical forces were a part of the joining and spliting of atoms and compounds. (http://www.abcte.org/files/previews/chemistry/s1_p3.html) (http://atomictimeline.net/index.php) -
Marie Curie
Marie Curie did research with radiation. She discovered that the amount of radiation depended on the of elements that was in the compound. She also won the Nobel Peace Prize multiple times for her great discoveries. (http://www.atomicheritage.org/profile/marie-curie) -
Henri Becquerel
Henri Becquerel discovered radioactivity. One type that he discovered was due to high-speed electrons leaving the neucleus.
(http://www.famousscientists.org/henri-becquerel/)
(http://atomictimeline.net/index.php) -
J.J. Thompson
J.J. Thompson discovered the electrons in the atom. He proposed a model called the plum pudding which was eventually proven to be false, but, he still had the right idea of negative electrons being a part of the atomic structure. (https://www.aip.org/history/electron/jjelectr.htm) (http://www.abcte.org/files/previews/chemistry/s1_p5.html) -
Max Planck
Max Planck discovered the Quantum Theory. This theory helped people understand the atomic and subatomic process.(http://atomictimeline.net/index.php) (http://www.britannica.com/biography/Max-Planck) -
Plum Pudding Model
The plum pudding model was created by J.J. Thompson. This model showed the atom having a positively charged liquid in the middle with negatively charged electrons surrounding it. (http://thehistoryoftheatomicmodel.weebly.com/plum-pudding-model.html) (http://www.universetoday.com/38326/plum-pudding-model/) -
Albert Einstein
Albert Einstein mathematically proved the existence atoms. He created the equation e=mc^2. (http://ansnuclearcafe.org/2012/03/20/albert-einstein-and-the-most-elemental-atomic-theory/) (http://atomictimeline.net/index.php) -
Robert Millikan
Robert Millikan measured the charge of the electrons. He measured this by using what is called an oil-drop apparatus. This discovery also helps prove Thompson's theory. (http://chemed.chem.purdue.edu/genchem/history/millikan.html) -
Ernest Rutherford
Ernest Rutherford proposed an atomic model that showed the structure of the atoms. It showed the atoms as tiny and dense with a positively charged nucleus and negatively charged electrons. (http://www.britannica.com/science/Rutherford-atomic-model) -
Planetary Model
The Planetary Model was made by Niels Bohr. This model showed the atom as having neutrons and protons in the nucleus with electrons orbiting the outside of the nucleus. (http://csep10.phys.utk.edu/astr162/lect/light/bohr.html) -
Otto Hahn
Otto Hahn discovered protactinium, and uranium Z. This was the first case of nuclear isomerism of radioactive atoms. He also made further discoveries with uranium including artificially active uranium and the fission of uranium. (http://www.atomicarchive.com/Bios/Hahn.shtml) -
Niels Bohr
Niels Bohr made an atomic model that showed the atoms as small with a positive nucleus and negative electrons. He made the discovery that electrons travel around the nucleus in seperate orbits. He also deiscovered that the number of electrons in the outer orbit determine the properties. (http://www.livescience.com/32016-niels-bohr-atomic-theory.html) (http://atomictimeline.net/index.php) -
Louis DeBroglie
Louis DeBroglie proposed the Theory of Electron Waves. This theory explained why the elctrons had restricted motion.
(http://www.britannica.com/biography/Louis-de-Broglie) (http://atomictimeline.net/index.php) -
Quantum Mechanical Model
The Quantum Mechanical Model was created by Max Planck. It showed where the electrons were likely to be located. This model was based a lot on probability because it was not possible to know the exact location of the electrons.
(http://www.sparknotes.com/testprep/books/sat2/chemistry/chapter4section4.rhtml) (http://www.dummies.com/how-to/content/atomic-structure-the-quantum-mechanical-model.html) (http://dwb.unl.edu/Teacher/NSF/C04/C04Links/www.fwkc.com/encyclopedia/low/articles/q/q021000030f.ht -
Ernest Schrodinger
Ernest Schrodinger came up with a model that predicts the location of the electrons. He used mathematical equations to predict this. (http://www.abcte.org/files/previews/chemistry/s1_p6.html) -
Electron Cloud Model
The electron cloud model was proposed by Erwin Schrödinger. This model was a dense nucleus surrounded by a cloud of electrons. (http://www.msnucleus.org/membership/html/jh/physical/atomictheory/lesson1/atomic1g.html) -
James Chadwick
James Chadwick discovered the neutron. He found this out by performing an experiment and noticing that the protons had been hit by electrically neutral particles that were similar to the protons. Those particles ended up being the neutrons. (http://www.famousscientists.org/james-chadwick/) (http://atomictimeline.net/index.php) -
Lisa Meitner
Lisa Meitner discovered nuclear fission. This is the discovery that shows that the atomic nucleus could be split to form more pairs of nuclei. (http://www.chemistryexplained.com/Ma-Na/Meitner-Lise.html)
(http://atomictimeline.net/) -
Glen T. Seaborg
Glen T. Seaborg discovered new elements such as plutonium. This discovery made people realize that the layout of the period table might need to be changed. (http://www.atomicarchive.com/Bios/Seaborg.shtml)
(http://atomictimeline.net/)