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1. Система Менделеева

2. новые элементы

3. профессор химии

4. интересные эксперименты

5. начал писать

6. тяжелая работа

7. химические элементы

8. Периодического закон

9. свои открытия

10. дальнейший прогресс

11. служит основой

12. выдающиеся исследования.
A Russian name appeared in 1964 on the honorary board of science at Bridgeport University, USA: Mendeleyev was added to the list of the greatest geniuses - Euclid, Archimedes, Copernicus, Galilei, Newton and Lavoisier. D.I. Mendeleyev, the explorer of nature, is the greatest chemist of the world. The Mendeleyev system has served for almost 150 years as a key to discovering new elements and it has retained its key capacity until now.

D.I. Mendeleyev was the fourteenth and the last child of the Director of the Gymnasium at Tobolsk. After finishing school at the age of 16 he was taken by his mother to St. Petersburg and entered the Pedagogical Institute in 1850, took a degree in chemistry in 1856 and in 1859 he was sent abroad for two years for further training. He returned to St. Petersburg in 1861 as Professor of Chemistry and gave a course of lectures on chemistry at St. Petersburg,s University. His lectures were always listened to with great interest and attention. Even in class of two hundred students everyone was able to follow his discussions from the beginning to the end. Interesting experiments were made in his classes.

In 1868 Mendeleyev began to write a great text book of chemistry, known in its English translation as "Principles of Chemistry" Hard work preceded it. Mendeleyev made thousands of experiments and calculations, wrote a lot of letters, studied many reports. Everything in the world that was known about chemical elements Mendeleyev knew. For months, for years he searched for missing data. All those data were being brought together and grouped in a special way. When compiling this, he tried to find some system of classifying the elements some sixty in all then known whose properties he was describing. This led him to formulate the Periodic Law: "The properties of elements and, consequently, the properties of the simple and complex bodies formed from them are periodic functions of their atomic weights". The Law earned him lasting international fame. He presented it verbally to the Russian Society in October 1868 and published 1869. But Mendeleyev was recognized as the author of the Periodic Law only after gallium, scandium and germanium had been discovered in France, Sweden and Germany and after the properties of number of elements predicted be Mendeleyev had been confirmed.

In this paper he set out clearly his discovery that if the elements are arranged in order of their atomic weights, chemically related elements appear at regular intervals. The greatness of Mendeleyev,s achievement lies in the fact that he had discovered a generalization that not only unified an enormous amount of existing information but pointed the way to further progress.

Today the Periodic Law is studied by millions of school children and by students at higher educational establishments of natural sciences and engineering. It is studied by philosophers, historians, teachers and chemists.

The law serves as a basis for thousands of researches. The Periodic Law crossed national boundaries and has become the property of all nations, just like the works of Newton, Lomonosow, Pavlov, Lobachevsky, Einstein and other. In our country the Russian Chemical Society, a number of higher and secondary schools, some industrial plants have been named after Mendeleyev. The Academy of Sciences and the Mendeleyev Society award the Mendeleyev Prize and the Mendeleyev Gold Medal for outstanding research work in chemistry.