1. THE HISTORY OF CHEMISTRY By: Mazin Marwan

2. 440 B.C. Leucippus and Democritus propose the idea of the atom. It is rejected in favor of Aristotle’s theory.

3. 350 B.C. Aristotle proposes that the world is made of 5 elements: fire, water, earth, air and aether. Aether being a pure element fit for gods and being the base for the other elements.

4. 1597 A.D. Andreas Libavius publishes an early version of a chemistry textbook.

5. 1789 A.D. Antoine Lavoisier publishes the first modern chemistry textbook.

6. 1860 A.D. Stanislao Cannizzaro compiles a table of atomic weights leading to Mandeleev’s discovery of periodic law.

7. 1800 A.D. John Dalton discovered that atomic theory could explain common patterns in chemistry and other complex things people didn’t understand back then.

8. 1800 A.D. Dalton proposed that that each element is made of atoms that are all the same. He said that they were indivisible yet destructible and when put together, they made some other type of reaction

9. 1805 A.D. Dalton publishes a paper that shows the relative atomic weights of the known elements. He got some of the atomic weights wrong because his equipment was crude compared to today’s and his way of thinking was wrong, he thought matter was, at the simplest, a combination of 2 single, different atoms\elements.

10. 1811 A.D. Amedeo Avogadro corrected the flaw in Dalton’s theory in 1811 when he showed that the mass of a gas’s particles does not affect the area it occupies. (at constant pressure and temperature)

11. 1897 A.D. J.J. Thomson discovered the electron while working on cathode rays. He concluded that cathode rays are electrons.

12. BIBLIOGRAPHY http://en.wikipedia.org/wiki/Atomic_theory http://photosinbox.com/sign-and-symbol/atom-2 http://tvpclub.blogspot.ca/2009/04/aristotles-physics-five-elements.html http://www.allvoices.com/contributed-news/6578068/image/61980998- aristotle http://www.allvoices.com/contributed-news/6578068/image/61980998- aristotle http://1000awesomethings.com/2013/02/26/823-when-you-find-out-what- was-making-that-horrible-smell-and-get-rid-of-it-2/ http://1000awesomethings.com/2013/02/26/823-when-you-find-out-what- was-making-that-horrible-smell-and-get-rid-of-it-2/ http://books-comics.bidstart.com/Modern-Chemistry-Textbook-by-Raymond- E-Davis-US-/17499078/a.html http://books-comics.bidstart.com/Modern-Chemistry-Textbook-by-Raymond- E-Davis-US-/17499078/a.html http://www.globalrph.com/periodic_table.htm http://www.fas.harvard.edu/~scidemos/QuantumRelativity/CathodeRayDefl ection/CathodeRayDeflection.html http://www.fas.harvard.edu/~scidemos/QuantumRelativity/CathodeRayDefl ection/CathodeRayDeflection.html http://profesorjamorgado.blogspot.ca/2011/04/unidad-didactica- estructura-del-atomo.html http://profesorjamorgado.blogspot.ca/2011/04/unidad-didactica- estructura-del-atomo.html

13. BIBLIOGRAPHY PART 2 http://www.hcc.mnscu.edu/chem/V.07/page_id_7029.html http://www.hcc.mnscu.edu/chem/V.07/page_id_33296.html