Примечания к тексту

1. Aristotle [ˈrsttl] – Аристотель (384–322)

2. B. C. (before Christ) – до нашей эры

3. confused ideas – сбивчивые представления

4. invert [nˈv:t] – переворачивать

5. fixation [fkˈse()n] – зд. поглощение

6. gifted [ˈgftd] – талантливый

7. to come to the conclusion – прийти к заключению

11. Расскажите о свойствах воздуха, пользуясь текстами 7 А и 7 В.

LESSON 8

Грамматика. Формы инфинитива. Субъектный инфинитивный оборот (сочетание глагола-сказуемого в страдательном залоге с инфинитивом).

Предтекстовые упражнения

1. Переведите следующие предложения на русский язык:

1. The composition of air is found to vary slightly with elevation. 2. The air is known to contain one fifth oxygen by volume. 3. Most substances have been found to expand as the temperature rises. 4. The temperature lower than -273° is not known to exist. 5. Water can be said to be a universal solvent. 6. Ground water has been stated to contain a great deal of impurities. 7. Water was believed by the ancients to be an element. 8. Oxygen can be said to represent the most widely distributed element on the Earth. 9. Hydrogen peroxide has been shown to resemble ozone in many ways. 10. Hydrogen peroxide is found to act both as a vigorous oxidizing agent and as a reducing agent. 11. Phosphorus and nitrogen have been proved by many experiments to differ radically in many respects. 12. Silicon is said to play an important part in the inorganic world. 13. The importance of carbon in organic chemistry is considered to result from its possessing the ability to form carbon-carbon bonds.

2. Прочитайте и переведите следующие предложения, обращая внимание на выделенные слова:

as compared (to, with) – по сравнению

The electrons and the nucleus are very small as compared with the size of the atom.

except (for) – за исключением

The chemical properties of ozone are similar to those of oxygen except for its greater chemical activity.

3. Прочитайте и переведите следующие слова без словаря:

portion [ˈpɔːʃ(ə)n], proton ['prətn], neutron [ˈnjuːtrn], electricity [ɪlekˈtrɪsɪtɪ], neutral [ˈnjuːtrəl], equal [ˈiːkwəl], mass [mæs], opposite ['pəzɪt], plus [plʌs], minus ['maɪnəs], diameter [daɪ'æmɪtə], centimeter (cm) [ˌsentɪ'miːtə]

4. Запомните чтение следующих слов:

indivisible [ˌɪndɪ'vɪzəbl], impenetrable [ɪm'penɪtrəbl], negligible ['neglɪʤəbl], sign [saɪn], whole [həl]

TEXT 8 A

Structure of Atoms

All kinds of matter are now known to consist of little particles called molecules; these molecules in turn are discovered to consist of still smaller particles called atoms. The name “atom” comes from the Greek word meaning “indivisible” because atoms were supposed to be completely indivisible. Until the end of the nineteenth century an atom was considered to be a “simple, solid, hard, impenetrable particle”. Now it is believed to contain (except for hydrogen) three kinds of particles, these occupying only a portion of the whole space of the atom. The particles are electrons, protons, and neutrons. The existence of these particles in the atoms of the elements is fully established.

Electrons are negatively charged. They are thought to lie in different groups about the nucleus of the atom.

If atoms of matter contain negative electricity it is evident that they must contain also positive electricity in an equal amount; otherwise they would not be electrically neutral.

The positively charged atom of hydrogen is a proton. The hydrogen atom is stated to contain only one electron and one proton, and when the electron is removed from the atom, only the proton remains. Since the electron’s weight is considered to be almost negligible, the mass of the proton is very nearly equal¹ to the mass of the hydrogen atom. The mass of the proton is found to be 1836 times greater than that of the electron. The electrical charge of the proton is equal in magnitude to the charge of the electron, but it has the opposite sign (+ instead of ˗ ² ).

The neutron has no charge at all and its mass is assumed to be approximately equal to that of the proton.

The electrons are the outer portion of the atom. The electrons and the nucleus are very small as compared with the size of the atom, which, therefore, appears to be composed largely of empty space. The diameter of the whole atom is estimated to be of the order of 10^-8 cm, while that of the nucleus is believed to be very much smaller.

The atomic weight of an element tells us the number of protons and neutrons in the nucleus of an atom. Now if we could determine the positive charge of the nucleus, we should then know the number of electrons in the atom, as the total charge of electrons is equal to the charge of the nucleus.