1800-1875

=John Dalton = =1766-1844 = Discovery: 1808 John Dalton was born around September 6th, 1766 (there are no exact record that exists) into a Quaker family in Eaglesfield, England. He was the youngest of three surviving children of a Quaker handloom weaver. He attended school until age 11 and once he turned 12, he became a teacher and a public lecturer. The first paper he delivered before the society was on color blindness, which afflicted him and is sometimes still called "Daltonism." After teaching for over ten years at Kendal, a Quaker boarding school, he taught in the city of Manchester. He was an English chemist providing the beginnings of the development of a scientific atomic theory. Dalton also contributed to physics, mostly meteorology.



Dalton's greatest achievement was the formulation of the atomic theory through a series if observations resulting from his preoccupation with gases. "It all began with the attempt to explaining why the constituents of a gaseous mixture remain homogeneously mixed instead of forming layers according to their density." Finally, in 1808 he published his //New System of Chemical Philosophy//.

1) All matter is made of atoms. Atoms are indivisible and indestructible. 2) All atoms of a given element are identical in mass and properties 3) Compounds are formed by a combination of two or more different kinds of atoms. 4) A chemical reaction is a rearrangement of atoms.
 * __Dalton's Atomic Theory (1808)__**

John Dalton’s Atomic Theory states that elements are made of tiny particles called atoms. He also formed an element set that was new to his time, but very simple compared to todays periodic table. His elemetal set was the basis for the periodic table, though he did not know it at the time.

Element Set:



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 * Michael Faraday **
 * 1791-1867 **
 * Discovery: 1832 **
 * Michael Faraday (1791-1867) **

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Michael Faraday was born in 1791 to a poor family in London. At age 13, he became an errand bot for a bookbinding shop in London. He read every book he bound and dicided he would write one some day. He was extremely interested in the concept of engery, secifically force. He is a British physicist and chemist, best known for his discoveries of electromagnetic induction and of the laws of electrolysis. His biggest breakthrough in electricity was his invention of the electric motor. He build two devices to produce what he called electromagnetic rotation: it is a continuous circular motion from the circular magnetic force around a wire. Ten years later, in 1831, he began his great series of experiments in which he discovered electromagnetic induction. These experiments form the basis of modern electromagnetic technology.



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In 1831, using his "induction ring", Michael Faraday made one of his greatest discoveries - electromagnetic induction: the "induction" or generation of electricity in a wire by means of the electromagnetic effect of a current in another wire. The induction ring was the first electric transformer. In a second series of experiments in September he discovered magneto-electric induction: the production of a steady electric current. To do this, Faraday attached two wires through a sliding contact to a copper disc. By rotating the disc between the poles of a horseshoe magnet he obtained a continuous direct current. This was the first generator. From his experiments came devices that led to the modern electric motor, generator and transformer. In 1832, he proved that the electricity induced from a magnet, voltaic electricity produced by a battery, and static electricity were all the same. He also did significant work in electrochemistry, stating the First and Second Laws of Electrolysis. This laid the basis for electrochemistry, another great modern industry.

Dmitri Mendeleev 1834-107 Discovery: 1863



[] Dmitri Mendeleev was born in Tobolsk, Siberia in 1834. He studied science at St. Petersburg and graduated in 1856. In 1866, he became the Chair in the University. Mendeleev is best known for his work on the periodic table. He arranged 63 known elements into a Periodic Table based on atomic mass, which he published in 1869 in //Principles of Chemistry//. He arranged the periodic table by increasing atomic weight and grouping them by similarity of properties. He also predicted the existence and properties of new elements and pointed out accepted atomic weights that were in error. He knew there were three elements that were for sure going to be discovered, so he left spaces for them. His tables, however, did not include any ofthe Noble Gases. Mendeleev anticipated Andrews' concept (1869) of the critical temperature of gases. He also investigated the thermal expansion of liquids, and studied the nature and origin of petroleum. He was considered one of the greatest teachers of his time. In 1890 he resigned his professorship and in 1893 became director of the bureau of weights and measures in St. Petersburg, where he remained until his death in 1907.

Mendeleev's Periodic table:

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Today's Periodic Table:

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