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Dimitri Mendeleev (Template:Lang-ru, Dimitriy Ivanovich Mendeleyev listen) (8 February [O.S. 27 January] 1834 in Tobolsk – 2 February [O.S. ] 1907 in Saint Petersburg), was a Russian chemist and inventor. He is credited as being the creator of the first version of the periodic table of elements. Unlike other contributors to the table, Mendeleev predicted the properties of elements yet to be discovered.

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Periodic table

After becoming a teacher, he wrote the definitive two-volume textbook at that time: Principles of Chemistry (1868-1870). As he attempted to classify the elements according to their chemical properties, he noticed patterns that led him to create his Periodic Table.

Unknown to Mendeleev, several other scientists had also been working on their own tables of elements. One was John Newlands, who published his Law of Octaves in 1865. However, the lack of spaces for undiscovered elements and the placing of two elements in one box were criticised and his ideas were not accepted. Another was Lothar Meyer, who published a work in 1864, describing 28 elements. Like Newlands, Meyer did not seem to have the idea of using a table to predict new elements. In contrast to Newlands' methodical approach to creating a table, Mendeleev's was almost accidental and emerged gradually.

As a better understanding of atomic mass was developed and better data became available, Mendeleev made for himself the following table:

By adding additional elements following this pattern, he developed his version of the periodic table.

On March 6, 1869, Mendeleev made a formal presentation to the Russian Chemical Society, entitled The Dependence between the Properties of the Atomic Weights of the Elements, which described elements according to both weight and valence. This presentation stated that

1. The elements, if arranged according to their atomic mass, exhibit an apparent periodicity of properties.
2. Elements which are similar as regards to their chemical properties have atomic weights which are either of nearly the same value (e.g., Pt, Ir, Os) or which increase regularly (e.g., K, Rb, Cs).
3. The arrangement of the elements in groups of elements in the order of their atomic weights corresponds to their so-called valencies, as well as, to some extent, to their distinctive chemical properties; as is apparent among other series in that of Li, Be, B, C, N, O, and F.
4. The elements which are the most widely diffused have small atomic weights.
5. The magnitude of the atomic weight determines the character of the element, just as the magnitude of the molecule determines the character of a compound body.
6. We must expect the discovery of many yet unknown elements–for example, two elements, analogous to aluminium and silicon, whose atomic weights would be between 65 and 75.
7. The atomic weight of an element may sometimes be amended by a knowledge of those of its contiguous elements. Thus the atomic weight of tellurium must lie between 123 and 126, and cannot be 128. Here Mendeleev was wrong as the atomic mass of tellurium (127.6) remains higher than that of iodine (126.9).
8. Certain characteristic properties of elements can be foretold from their atomic weights.

Only a few months after Mendeleev published his periodic table of all known elements (and predicted several new elements to complete the table), Meyer published a virtually identical table. Some people consider Meyer and Mendeleev the co-creators of the periodic table, although most agree that Mendeleev's accurate prediction of the qualities of what he called ekasilicon (germanium), ekaaluminium (gallium) and ekaboron (scandium) qualifies him for deserving the majority of the credit for studies.

As others before him had done, he questioned the accuracy of accepted atomic weights, pointing out that they did not correspond to those predicted by the Periodic Law. He noted that tellurium has a higher atomic weight than iodine, but he placed them in the correct order, assuming that the accepted atomic weights at the time were incorrect. He was puzzled about where to put the known lanthanides, and predicted the existence of another row to the table, the actinides, which were some of the heaviest in atomic mass.

Initially, Mendeleev was derided for there being gaps in the table. Ultimately though, he was vindicated when previously unknown elements (notably scandium, gallium and germanium) were discovered that filled in these holes and possessed properties (atomic weight, density, melting point, etc.) close to what Mendeleev predicted.

Henry Moseley would later help put the periodic table on the correct basis of atom number rather than atomic weight.

Other achievements

Mendeleev made other important contributions to chemistry. The Russian chemist and science historian L.A. Tchugayev has characterized him as "a chemist of genius, first-class physicist, a fruitful researcher in the fields of hydrodynamics, meteorology, geology, certain branches of chemical technology (explosives, petroleum, and fuels, for example) and other disciplines adjacent to chemistry and physics, a thorough expert of chemical industry and industry in general, and an original thinker in the field of economy." Mendeleev was one of the founders, in 1869, of the Russian Chemical Society. He worked on the theory and practice of protectionist trade and on agriculture.

In an attempt at a chemical conception of the Aether, he put forward a hypothesis that there existed two inert chemical elements of lesser atomic weight than hydrogen. Of these two proposed elements, he thought the lighter to be an all-penetrating, all-pervasive gas, and the slightly heavier one to be a proposed element, coronium.

Mendeleev devoted much study and made important contributions to the determination of the nature of such indefinite compounds as solutions.

In another department of physical chemistry, he investigated the expansion of liquids with heat, and devised a formula similar to Gay-Lussac's law of the uniformity of the expansion of gases, while as far back as 1861 he anticipated Thomas Andrews' conception of the critical temperature of gases by defining the absolute boiling-point of a substance as the temperature at which cohesion and heat of vaporization become equal to zero and the liquid changes to vapor, irrespective of the pressure and volume.

Mendeleev is given credit for the introduction of the metric system to the Russian Empire.

He invented pyrocollodion, a kind of smokeless powder based on nitrocellulose. This work had been commissioned by the Russian Navy, which however did not adopt its use. In 1892 Mendeleev organized its manufacture.

Mendeleev studied petroleum origin and concluded that hydrocarbons are abiogenic and form deep within the earth. He wrote: "The capital fact to note is that petroleum was born in the depths of the earth, and it is only there that we must seek its origin." (Dmitri Mendeleev, 1877)

See also

• Mendeleev's predicted elements
• Abiogenic petroleum origin

Further reading

• Gordin, Michael (2004). A Well-Ordered Thing: Dmitrii Mendeleev and the Shadow of the Periodic Table. New York: Basic Books. ISBN 0-465-02775-X.
• Mendeleev, Dmitry Ivanovich (2005). Mendeleev on the Periodic Law: Selected Writings, 1869 - 1905. Mineola, NY: Dover. ISBN 0-486-44571-2. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
• Strathern, Paul (2001). Mendeleyev's Dream: The Quest For the Elements. New York: St. Martins Press. ISBN 0-312-26204-3.
• Scerri, Eric (2007). The Periodic Table: Its Story and Its Significance. New York: Oxford University Press. ISBN 0-312-26204-3.

References and external links

Biographies

• Roger Rumppe and Michael E. Sixtus, "Ich bin Mendelejeff", care of the Woodrow Wilson Leadership Program in Chemistry. 20 sources. Notes, among other things, that various sources list D.M.'s siblings as being 10 to 16 in number.

Periodic table

• Original Periodic Table, annotated
• Mendeleev's first draft version of the Periodic Table, 17 February 1869

Other

• References about Mendeleev, maintained by Eugene V. Babaev, last updated May 2005 (as of December 2005).
• Faraday Lecture by Mendeleev, July 4, 1889, annotated
• Mendeleev and Sanskrit
• Picture of Mendeleev, Edgar Fahs Smith Collection, University of Pennsylvania
• Everything in its Place
• Mendeleev profile at thinkquest.org
• Dmitri Ivanovich Mendeleev article on h2g2.
• Who was Dmitri Mendeleev?
• Photographs of the Mendeleev family's now dilapidated house
• Video of a talk by Michael Gordin titled "Periodicity, Priority, Pedagogy: Mendeleev and Lothar Meyer"

Notes

1. Emsley, John (2001). Nature's Building Blocks ((Hardcover, First Edition) ed.). Oxford University Press. pp. 521–522. ISBN 0198503407.
2. Mendeleev, D., 1877. L'Origine du pétrole. Revue Scientifique, 2e Ser., VIII, p. 409-416.

• Russian chemists
• Russian scientists
• Alumni of St. Petersburg State University
• Russian inventors
• Recipients of the Copley Medal
• Alumni and faculty of Saint Petersburg Technological Institute
• 1834 births
• 1907 deaths