2. Look through the text again and find the sentences where the author de­scribes the following facts:

1. Mendeleyev could foresee the existence of new elements because he was very gifted.

2. Scientists of Mendeleyev's time didn't believe that elements are connected with each other.

3. Mendeleyev's character made him order the elements.

4. Mendeleyev's work on the Periodic Table and the Periodic Law has long interested scientists.

5. There were some scientists’ attempts to find a system to order the elements but they failed.

6. Thanks to Mendeleyev modern chemistry uses the clearly developed Periodic System as the main instrument.

2. Read the text thoroughly with a dictionary and answer the following ques­tions choosing the correct answer out of the given ones:

1. Where did Mendeleyev start ordering the elements?

a) at school;

b) at St. Petersburg University;

c) abroad.

2. Why did Mendeleyev turn to ordering the elements? Because:

a) other scientists’ attempts failed;

b) he had talent;

c) he didn’t like disorder.

3. What did the researchers try to do to find some order of the ele­ments?

a) they compared different properties;

b) they read scientific literature;

c) they denied (опровергали) the earlier attempts of the scientists.

4. How did Mendeleyev list the elements?

a) according to their names;

b) according to their atomic weights;

c) according to their chemical symbols.

5. What did scientists of Mendeleyev’s time think about atoms of dif­ferent elements?

a) they were independent particles of nature;

b) they were closely connected;

c) they belonged to a well-ordered system.

2. Give Russian equivalents to the following words, word combinations and chemical terms from the text:

1. research worker 2. well-ordered

3. majority 4. firmly

5. were convinced 6. particles

7. advanced 8. realized

9. unsuccessful 10. to exercise

11. to influence 12. could not bear

13. had been appointed 14. disorder

15. comparison 16. according

17. similarity 18. applied

19. increasing 20. insight

21. for example 22. weight

23. tools 24. nucleus

25. lucidly 26. density

2. Match the synonyms in ex. 5 and ex. 6:

a) to affect b) investigator

c) were sure d) unlucky

e) resolutely f) progressive

g) had been given a position h) instruments

i) for instance j) centre

k) very small bits l) understood

m) to exert n) chaos

o) likeness p) making greater

q) collation r) properly organized

s) in agreement with t) thickness

u) used v) disliked very much

w) intuitive cognition x) heaviness

y) clearly z) a greater number

2. Find in the text all the sentences containing the sequence of tenses. Translate them into Russian.

2. A) Translate the following sentences into Russian:

1. The scientist said that our age was the age of chemistry.

2. The ancient Greek philosophers thought that matter consisted of infinitely small particles.

3. Aristotle believed that his theory would agree with the general views on nature.

4. After Copernicus and Galileo everybody could know that the Earth turns round the Sun.

5. Cavendish discovered that water consists of a definite proportion of hydrogen and oxygen.

6. Few scientists of that time knew that Mendeleyev had discovered the Periodic System of Elements.

7. It was reported that those interesting experiments would initiate series of similar investigations.

8. The professor said that they had found some unknown properties of that substance.

9. It was reported that the new element would occupy the definite place in the Periodic Table.

10. They assumed that their method of investigation could be applied in many experiments.

b) Translate the following sentences into English:

1. Профессор сказал, что этот эксперимент проводится для ил­люстрации его доклада.

2. Студенты сказали, что узнали о новом открытии на семинаре.

3. Преподаватель знал, что несколько студентов станут иссле­дователями.

4. Ученые были уверены, что некоторые открытия повлияли на научные взгляды Менделеева.

5. Несколько прогрессивных ученых понимали, что существует определенная система элементов.

6. В своей книге Б. Н. Конарев доказывает, что в древности люди знали только те вещества, которые были им необходи­мы для жизни.

7. Арабские алхимики уже в IX—X вв. считали, что все вещества можно разделить на органические и неорганические.

8. Лавуазье ответил на те вопросы, на которые не могли найти ответы ученые нескольких поколений.

9. Преподаватель рассказал на лекции, какой вклад внес Берцелиус в неорганическую химию.

10. Мы знаем, что Берцелиус был автором нескольких учебников по химии.