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  1. Read the following text attentively and choose the most suitable title out of the given ones:

1. History of Scientific Discoveries.

2. Mendeleyev's Contribution to Chemistry,

3. Elements of the Periodic Table.

4. The Periodic System of Elements.

In spite of the importance of the contributions that had been made earlier, the greatest portion of credit for the development of the Periodic System must undoubtedly go to the Russian scientist, D. I. Mendeleyev. The understanding that the properties of the elements can be repre­sented as periodic functions of their atomic weights made possible classification that has suffered few significant changes in the subse­quent years. In March of 1869 D. I. Mendeleyev published his first de­scription of the Periodic System in which he gave the arrangement of the elements in terms of their increasing atomic weights. He fully real­ized the importance of this periodicity. In his first article D. I. Men­deleyev pointed out the similarities of a number of properties of certain elements and changed the order of atomic weights where necessary in order to have the group similarity. D. I. Mendeleyev left vacant posi­tions in his table for yet undiscovered elements and expressed the opinion that the chemical and physical properties of the elements would be discovered, as he predicted, from their positions in the table. In the summer of 1871 D. I. Mendeleyev published a more compre­hensive work and called it the Periodic Law. At this time he presented the more familiar form of the Periodic Table and although it differs somewhat from the one we use today, it is in general the same. In his publication of 1871 D. I. Mendeleyev used the periodic character to predict the properties of the elements which would be later described as those of scandium, gallium, and germanium. The remarkable agreement of the properties of these elements as they had been described by Mendeleyev and those that were observed later is without doubt a complete justification of D. I. Mendeleyev's faith in his Periodic Law. In December 1945 Glenn Seaberg made his first publication of a Periodic Table which described a new actinide series beginning with actin­ium. He said that American scientists were proud and happy to honour the name of D. I. Mendeleyev by calling element 101 "mendelevium".

  1. Read the text again and list the points of the given plan in the order of events they occur in the text:

Plan:

1. Advent of the Periodic Law.

2. Discovery of "Mendelevium". :

3. Similarities of Elements' Properties.

4. The Inventor of the Periodic System of Elements.

  1. Read the text for the third time, write out the main sentence(s) of each log­ical part and translate them into Russian.

  1. Combine the sentences you've written out into a summary. Then rewrite them in your own words, omitting unnecessary details.

Unit VII

Russian achievements in science Part a

  1. Learn the following words.

to enrich (with) – обогащать

to enable – давать возможность, способствовать

to solve – решать

to establish – основывать, создавать

to elaborate – тщательно разрабатывать

to extract – извлекать

to set up – основывать, открывать, учреждать

recognition – признание, известность

overall volume of production – общий объем производства

large scale production – производство большого масштаба

branch – отрасль

simultaneously - одновременно

artificial – искусственный