dmitri mendeleev

MENDELEEV, DMITRI IVANOVICH

 (1834 - 1907).

 discovery of the periodic law and his periodic table of the elements was first announced to European scientists in a short article in the german journal Zeitschrift fur Chemie (Journal of Chemistry) in 1869, which is on display. Mendeleev discovered the periodic law during the time he was engaged in writing the first edition of a chemistry textbook, Osnovy Khimii (Principles of Chemistry). Mendeleev based his periodic table on 'four aspects of matter' that revealed close relationships between certain chemical elements. These four aspects were isomorphism, the specific volumes of similar compounds or elements, the composition of compound salts, and relations among the atomic weights of elements. Since the periodic law was dependent upon the quantitative relation between atomic weight, as an independent variable, and an element's physical and chemical properties, Mendeleev in 1869 took up the problem of developing and entire 'natural system of elements'. He employed deduction to reach the boldest and most far-reaching logical consequences of the law that he had discovered, so that he might, by verification of these consequences, confirm the law itself. Among these consequences were predictions of the chemical properties of several unknown elements. Two of these elements, which we now know as gallium and germanium, were discovered in the 1870s and possessed almost exactly the properties Mendeleev had predicted for them. Mendeleev's periodic table is one of the most important chemical discoveries of the nineteenth century; it remains today a central unifying principle in the science of chemistry. The first edition of Osnovy Khimii (shown here) is exceedingly rare as only about six copies exist in the US. The copy on display is unusual in that volume 2 is evidently a previously unrecorded first issue. It consists of only the first half of volume 2, the title page is green instead of the usual white, and the publication date is 1870 instead of the usual 1871. The title page says that this is the third part of Osnovy Khimii, the first two parts evidently corresponding to what normally is issued as volume 1. This part 3 is complete, as judged from the fact that the number of illustrations indicated on the title page agrees with the number that appear in the text. The large folding table, which was included in the 1871 issue of the full volume 2, is missing in this present copy. Presumably, the folding table, which consists of an improved version of the 1869 periodic table that appears in volume 1, was not devised until after 1870

Mendeleev predicts new elements!

He actually predicted that these gaps would be filled by elements yet to be discovered. He called these elements eka-silicon, eka-aluminium and eka-boron. What's more, he suggested what they would be like - their reactions, their weights and densities. It caused a huge shock to scientists.

...and gets proved right!

No one believed Mendeleev until a French chemist called Emile Lecoq came along. He had discovered an element which he named gallium. It weighed as much as Mendeleev's predicted eka-aluminium. As he studied it more, it behaved exactly like Mendeleev had said. It had the same reactions, and the same density. And then another element was discovered which behaved exactly like eka-silicon. It is now called germanium.

Both happened while Mendeleev was quite alive, so he had the joy of being proved right. Because of this, he is often considered one of the best theoretical chemists ever.

Mendeleev never took any care of his personal appearance, dressing shabbily and never cutting his hair. His colleagues got the Russian Emperor to invite him to the palace, hoping that Mendeleev would smarten up for the meeting. But he turned up in his shabby coat and unkempt hair, and the emperor could do nothing!

Mendeleev's Life

Mendeleev's story is a very inspiring one. Born on 8 February 1834, he was the 14th child of a very poor family from Tobolsk in Siberia. When he was just 13 his father died, so his family had to shift to St. Petersburg to find work. But he rose from his situation, completed his education and started a long and celebrated carrer in chemistry. In 1865, he was appointed Professor of Chemistry at St. Petersburg University. In that time he made his most famous discoveries, and made St. Peterburg an exciting place to study Chemistry anywhere in the world.

He died in 1907.