Dmitri Ivanovich Mendeleev (born: February 7, 1834 / died: January 20, 1907)
|Dmitri Ivanovich Mendeleev was a Russian chemist who became known
as one of two scientists who created the first version of the Periodic Table
of Elements. Mendeleev stated that the elements were arranged in a very unique
pattern which allows him to predict the elements before they are discovered.
He was born in Tobolsk, Siberia, the youngest of fourteen children of Maria Dmitrievna Korniliev and Ivan Pavlovitch Mendeleev. At the age of 14, after the death of his father, Mendeleev was attending the Gymnasium in Tobolsk. In 1849, the now poor family Mendeleev relocated to St. Petersburg, where he entered university in 1850.
|After graduating, a sickness that was diagnosed as tuberculosis made
him move to the Crimean Peninsula near the Black Sea in 1855 as chief science
master of the local gymnasium, but 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 Nikitchna Lascheva.
|In 1866, Newlands published his Law of Octaves. Mendeleev 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 :
i) The elements, if arranged according to their atomic weights, exhibit an apparent periodicity of properties.
ii) Elements which are similar as regards their chemical properties have atomic weights which are either of nearly the same value (eg. Pt, Ir, Os) or which increase regularly (eg. K, Rb, Cs).
iii) 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.
iv) The elements which are the most widely diffused have small atomic weights.v) 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.
vi) 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.
vii) 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.
Certain characteristic properties of elements can be foretold
from their atomic weights.
Though Mendeleev was widely honored by scientific organizations all over Europe, 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.
He died in St. Petersburg, Russia.Element 101 is named after him.