Dmitri Mendeleev

Dmitri Ivanovich Mendeleyev (Russian: Дми́трий Ива́нович Менделе́ев Template:Audio) (February 1834–Feb 2 1907), Russian chemist who became known as one of two scientists who created the first version of the periodic table of elements. Unlike any other contributors to the table, he managed to predict the properties of elements yet to be discovered. In several cases he even ventured to question the correctness of the accepted atomic weights, on the ground that they did not correspond with the Periodic Law, and here also he was justified by subsequent investigation.

Contents

1 Biography 2 Periodic Table 3 Other achievements 4 External links

Biography

Mendeleyev was born in Tobolsk, Siberia, the youngest of fourteen children of Ivan Pavlovich Mendeleyev and Maria Dmitrievna Mendeleeva (nee Kornilieva). At the age of fourteen, after the death of his father, Mendeleyev attended the Gymnasium in Tobolsk.

In 1849, the now poor family Mendeleyev relocated to St. Petersburg, where he entered the Main Pedagogical Institute in 1850. After graduating, an illness that was diagnosed as tuberculosis caused him to move to the Crimean Peninsula near the Black Sea in 1855, where he became chief science master of the local gymnasium. He returned with fully restored health to St. Petersburg in 1856.

Between 1859 and 1861 he worked on the density of gases in Paris, and the workings of the spectroscope with Gustav Robert Kirchhoff in Heidelberg. In 1863, after returning to Russia, he became Professor of Chemistry at the Technological Institute and the University of St. Petersburg. In the same year, he married Feozva Nikitichna Leshcheva; the marriage ended in divorce. He later married Anna Ivanovna Popova; their daughter Lyubov eventually became the wife of the famous Russian poet Alexander Blok.

Though Mendeleyev was widely honored by scientific organizations all over Europe, including the Copley Medal from the Royal Society of London, his political activities worried the Russian government, which led to his resignation from St. Petersburg University on August 17, 1890. In 1893, he was appointed Director of the Bureau of Weights and Measures.

In his later years, he worked out and patented the standard for the classical Russian vodka. Perhaps more importantly, he investigated the composition and fields of oil and helped to found the first oil refinery in Russia. He died in St. Petersburg, Russia from influenza. Element number 101, the radioactive mendelevium, is named after him.

Periodic Table

In 1866, Newlands published his Law of Octaves. 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. Unaware of this, Mendeleyev had been working on a similar idea, and on March 6, 1869, a formal presentation was made to the Russian Chemical Society, entitled The Dependence Between the Properties of the Atomic Weights of the Elements, stating

1. The elements, if arranged according to their atomic weights, 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, or of 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, Ba, C, N, O, and Sn.
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 as yet unknown elements–for example, elements analogous to aluminum and silicon–whose atomic weight 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.
8. Certain characteristic properties of elements can be foretold from their atomic weights.

Unknown to Mendeleyev, Lothar Meyer was also working on a periodic table. In his work published in 1864, Meyer presented only 28 elements, classified not by atomic weight but by valence alone. Also, Meyer never came to the idea of predicting new elements and correcting 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, plus some corrected atomic weights), Meyer published a virtually identical table. Some people consider Meyer and Mendeleyev the cocreators of the periodic table, although most agree that Mendeleyev's accurate prediction of the qualities of what he called eka-silicon (germanium), eka-aluminum (gallium), and eka-boron (scandium) lands him the lion's share of credit. In any case, at the time Mendeleyev's predictions greatly impressed his contemporaries and were eventually found to be correct.

Other achievements

In 1902, in an attempt at a chemical conception of the ether, he put forward the hypothesis that there are in existence two elements of smaller atomic weight than hydrogen, and that the lighter of these is a chemically inert, exceedingly mobile, all-penetrating and all-pervading gas, which constitutes the aether.

Mendeleyev also devoted much study to the nature of such indefinite compounds as solutions, which he looked upon as homogeneous liquid systems of unstable dissociating compounds of the solvent with the substance dissolved, holding the opinion that they are merely an instance of ordinary definite or atomic compounds, subject to Dalton's laws.

In another department of physical chemistry he investigated the expansion of liquids with heat, and devised a formula for its expression similar to Gay-Lussac's law of the uniformity of the expansion of gases, while so far back as 1861 he anticipated T. Andrews's 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 vapour, irrespective of the pressure and volume.

Mendeleyev wrote largely on chemical topics, his most widely known book probably being The Principles of Chemistry, which was written in 1868-1870, and has gone through many subsequent editions in various languages.

Mendeleyev is often credited for the scientific justification of the "optimal" ratio of alcohol of 40% (80 proof) used in vodka. The source for the attribution was his doctorate thesis "On Composing Alcohol with Water". The thesis dealt primarily with the physical properties of water-alcohol solutions, such as density.

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

He had invented pyrocollodium, a kind of smokeless powder based on nitrocellulose, and in 1892 organised its manufacture.

External links

• More about Mendeleev (http://www.chem.msu.su/eng/misc/mendeleev/welcome.html)
• Mendeleev and Sanskrit (http://uk.arxiv.org/abs/physics/0411080)
• Picture of Mendeleev (http://dewey.library.upenn.edu/sceti/smith/imagedetail.cfm?PictureID=301&Position=1&keywords=mendeleev&subcoll=), Edgar Fahs Smith Collection, University of Pennsylvania
• Original Periodic Table (http://webserver.lemoyne.edu/faculty/giunta/EA/MENDELEEVann.HTML), annotated
• Mendeleev's first draft version of the Periodic Table (http://www.chemheritage.org/EducationalServices/chemach/ppt/lm01.html), 17 February 1869
• Faraday Lecture (http://webserver.lemoyne.edu/faculty/giunta/EA/MENDELann.HTML) by Mendeleev, July 4, 1889, annotated
• A Well-Ordered Thing: Dmitrii Mendeleev and the Shadow of the Periodic Table (http://www.amazon.com/exec/obidos/tg/detail/-/046502775X), a book by Michael Gordin

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