Тема 2. «Периодический закон д. И. Менделеева». «Атом. Атомная модель. Планетарная модель атома» Module 2

Task 1. Remember the following words and word combinations:

ferrous metals – черные металлы evolve – развиваться achievement – достижение oxidizing power – окислительная способность according to – согласно, в соответствии с atomic number – атомный номер arrangement – устройство, порядок

number of – несколько сontribution – вклад numerous – многочисленный рractice – заниматься salt – соль row – ряд bond – химическая связь replace – перемещать improve – улучшать column – колонка, столбец

Task 2. Read international words. Mind pronunciation:

numerous, thesis, theory, material, atom organic, inorganic, reaction, technical, progress, element, isotope, thermal, experiment, practice, ion, polymer, plastics, industrial, global, result, physics, metallic

Task 3. Open the brackets choosing the correct form of the adjective. Translate the sentences into Russian:

1. Atoms are not (smaller, the smallest) particles, but they are very small.

2. This discovery is (more important, the most important) than the previous one.

3. It is much (easier, the easiest) to make parts of plastics than of metal or wood.

4. This is (better, the best) laboratory in our Institute.

5. Aluminum is (lighter, the lightest) known metal.

6. Hydrogen is (lighter, the lightest) of the elements.

7. Beryllium is (less, the least) active member of the group, and there is a regular increase in activity from metal to metal in the order of increased atomic numbers.

8. Moscow University is (larger, the largest) University in our country.

9. (More, the most) characteristic chemical property of hydrogen peroxide is its great oxidizing power.

Task 4. Translate the sentences into Russian. Mind the use of "most":

1. In the dye solution most dyes go into colloidal suspension.

2. In most carbon compounds only one valence bond is held between adjacent carbon atoms.

3. The discovery of steel was one of the most important inventions of man, for it gave him one of the hardest materials.

4. In the atmosphere oxygen is for the most part uncombined.

5. Most of the interior of an atom can be considered as an empty space, similar to that between the planets.

6. Many ions, probably most of them, are hydrated in aqueous solution.

7. The most convenient method was that used by our scientists.

8. The most extensive use of ammonium sulphate is in plant fertilizers.

9. Most of our students take an active part in the preparation for this conference.

10. Unlike most salts the solubility of anhydrous salt decreases with the rise in temperature.

Task 5. Read the text and answer the following questions

1. What is the periodic table?

2. What is the main principle of the elements presentation in the periodical table?

3. What is the “standard form” of the table?

4. When was the number of elements in the table kept increasing?

5. Who came to the same conclusion as D. I. Mendeleev?

6. How were the elements grouped in 1869? What was the following step?