19th century chemistry

The 1800s produced order and a vital understanding of proportions and standards in chemistry.  The most significant of these was the idea of the periodic table, the universal classification method of the elements.  


Dmitri Ivanovich Mendeleev (1837-1907) (see left) generally has the credit for this, following the work of many previous European chemists – Döbereiner (1780-1849), Kekule von Stradonitz (1829-1886), Cannizzaro (1826-1910), Newlands (1837-1898) and Meyer (1830-1895).  


Mendeleev: image reproduced from http://dbhs.wvusd.k12.ca.us/gallery/html


"Once there lived and existed a great learned man with a beard almost as long as God's. And one day the people came to this man and said 'Go to the Lord, and tell him of our misery.' 'I will go,' said the man. So he caught a great bubble, and sat down on top of it, and flew up and up until he pierced the heaven above us. And there he saw God and told him of our misery and God pardoned our sins and lightened our burdens. Then the great bearded man came down from the heavens and the people were happy. And for this, the authorities and the tsar made this man a very great scientist."                                                                                                                      Posin, D. 1948 Mendeleev, The Story of a Great Chemist, Whittlesey House

By the end of the century much work had been put into developing the observation that compounds contained specific proportions of the elements of which they were composed.  This led to the ‘Law of definite Proportion’ and later the ‘Law of Multiple Proportions’ by Joseph Louis Proust (1754-1826) and John Dalton (1766-1844) (see below)  respectively.  This was of great mathematical significance in the world of chemistry.



The late 1800s also marked the development by John Dalton of Avagadro’s Hypothesis, the idea that balanced equations were necessary to produce a certain amount of products from a certain amount of reactants. 


Dalton: image reproduced from http://dbhs.wvusd.k12.ca.us/gallery/html


Another important development of the century was in the field of electrochemistry, particularly by Michael Faraday (1791-1867), who defined electrolysis, electrolyte, electrode, anode, cathode, anion and cation, and who identified the concept of an electron, and who independently proposed the first and second Laws of Electrolysis.  This paved the way for future electrochemists.


20th century chemistry

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