D.I. Mendeleyev — pride of russian science

The list of spheres of knowledge which Mendeleyev's genius touched upon is enormous. Chemistry, physics, earth sciences, metrology, economics, metallurgy and much else.¹ Mendeleyev's legacy comprises 25 volumes, a third of them devoted to chemistry.

D.I. Mendeleyev, the outstanding Russian scientist, was born in Tobolsk in 1834. In 1850 at the age of 16 he entered the Pedagogical Institute in St. Petersburg to study chemistry. Five years later he gradu­ated from it with a gold medal and was invited to lecture on theoretical and organic chemistry at St. Petersburg University. To continue his stud­ies and research Mendeleyev was sent to Germany in 1859. While living abroad he made a number of² important investigations.

The year 1868 was the beginning of his highly important work "Fundamentals of Chemistry". When working at the subject Mendeleyev ana-lysed an enormous amount of literature, made thousands of experiments and calculations. This tremendous work resulted in the Table of Eler ments consisting of vertical ; groups and horizontal periods. Mendeleyev was the first to suggest a system of classification in which the elements are arranged in the order of increasing atomic weights. The main idea of the Periodic System is the idea of periodic repetition of properties with the increase of the atomic weights.

Arranging all the existing elements in the Table Mendeleyev had to overcome great difficulties, as a considerable number of elements were unknown at that time and the atomic weights of 9 elements (out of 63) were wrongly determined. Thanks to his investigations Mendeleyev was able to predict not only the existence of a few unknown elements but their properties as well. Later the elements predicted were discovered.

More than 350 works created by Mendeleyev deal with a great many subjects. Combining theory with practical activities he carried out enor­mous research in coal, iron and steel industries in Russia. He died in 1907 at the age of 73. The achievements in chemistry and physics at the end of the 19th and the beginning of the 20th century made it necessary to reconstruct the Periodic Table taking into account³ new discoveries.

Time is the severest judge in science. After more than 100 years of its existence, the Periodic Law has preserved its full value and is being constantly developed with each new discovery.

Unit 15

Igor kurchatov (1903—1960)

Among our famous atomic scientists the first place belongs by right¹ to Academician Igor Kurchatov. Everybody knows that it was he who laid the foundation of the atomic might of Russia. At the same time Fermi started to work at splitting nucleus and in 1939 he showed that when uranium nucleus was split by slow neutrons, two-three fast neutrons were emitted. Taking into consideration this phenomenon Fermi managed to carry out in practice the nucleus chain reaction in December 1942.

Since 1925 I.V. Kurchatov began of work at the Physical-Engineering Institute! in Leningrad. It was here that he achieved! great results in the research of dielectrics f which had been little known at that time. As far as the early thirties² atomic research was being successfully conducted in the Soviet Union. Soviet nuclear physics was in need of a powerful source of fast particles; capable of inducing a nuclear reaction. A, group of young research workers, with I. Kurchatov at the head, began investigating the physics of the nucleus of the: atom. Their investigations led to a striking discovery of fission of uranium nucleus.

I. Kurchatov understood that the neutron was the key to splitting the atom and he put all his efforts into neutron research. In 1940 I. Kurchatov came to the conclusion that slow neutron chain reaction was quite possible. But World War II interrupted his work, and all research programs had to be suspended. During the war I. Kurchatov gave all his energy and knowledge to the strengthening of military might of our Motherland.

In 1949 the Soviet Government announced that the secret of the atom bomb no longer existed and the USA had lost its atomic monopoly. It was decided that Soviet scientists would continue their work in the field of atom application for peace.

On June 27, 1954, the first atomic power plant in the world was put into operation near Moscow. This power generating installation based on the uranium-graphite reactor was Kurchatov's favourite invention. Later he was carried away by another great idea — to master controlled thermonuclear reactions and he declared that the second half of the 20th century would be the era of thermonuclear energy.

I. Kurchatov died in I960 but his experience and his knowledge J have become immortalized in the world's first atomic power plant, in atom-driven ice-breakers, in Dubna Institute and in the broad development of thermonuclear research in our country.