A Pattern for the Elements

In spite of the fact that elements and their atoms consist of different parts and can be decomposed, the elements are the building stones of which all matter is constructed. The same type of elements form the earth s crust, the water in the oceans, the high-temperature alloys in airplane engines, the material in plastic cups and the matter in the compHcated structures of living things. 

Dimitri) Mendelejev was bom in Tobolsk, Siberia on February 7, 1834. He was the youngest of 14 children in one of the pioneer families, whose duty it was to transform the eastern provinces of the huge Russian empire. His father was Principal of the local high school in Tobolsk. He died and Dimitrij s 

Perhaps the older brothers and sisters had to take care of each other. Their mother was determined to give young Dimitrij the opportunity to study science, and she tried, without success, to get him approved as a student at the University of Moscow. She traveled with him further to St Petersbmg. There he was given the opportunity to study mathematics, physics and chemistry and was so successfirl that he was offered the chance to travel in Europe to further improve his knowledge. In Heidelberg he learned spectroscopy from Bunsen and Kirchhoff At the age of 32, in 1866, he was appointed professor of chemistry at the University of St Petersburg. He wrote a book Principles of Chemistry and founded the Russian Chemical Society in 1868. Above all, however, he is remembered for The Periodic System of the Elements. 

Mendelejev s work was admirable. The system he created made it possible for him to draw bold conclusions about facts beyond the actual experimental results, limited as they were at that time. Some examples  

Beryllium, discovered in 1797 by Vauquelin in Paris, very much resembled aluminum, discovered by Oersted in Copenhagen in 1825. The similarity led chemists to suppose that beryllium was trivalent like aluminum. There was, however, no place in Mendelejev s system for a trivalent atom with beryllium s atomic weight Because of that, Mendelejev placed Be in group 2, which would imply a normal oxidation state of 2 for the metal in spite of the similarity with aluminum. Later chemical research proved that his opinion had been right 

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