3 Part One. The Predicate

The Bohr Theory o f the Hydrogen Atom
Most our knowledge of the electronic structure of atoms has been obtained by the study of the light given out by atoms when they are cxcitcd by high temperature or by an electric are or spark. The light that is emitted by atoms of a given substance can be rcfraetcd or diffracted into a distinctive pattern of lines of certain frcqucncics; such a distinctive pattern of lines is said to be the line spectrum of the atom.

The careful study of line spectra began about 1880. Early investigators made some progress in the interpretation o f spectra, in recognizing regularities in the frcqucncics o f the lines; the frcqucncics o f the spectral lines of the hydrogen atom, for example, show an especially simple relationship with one another. It was not until 1913, however, that the interpretation of the spectrum of hydrogen in terms o f the electronic structure of the hydrogen atom was achieved. In that year, die Danish physicist Niels Bohr (1885-1962) successfully applied the quantum theory to this problem, and laid the basis for the extraordinary advancc in our understanding of the nature of matter that has been made since then.

Mashq 3. Matnning asosiy tarkibini bir nechta jumlalarda ko'rsating.

Mashq 4. Matnning rejasini tuzing.

Mashq 5. Jumlalarni o'qing va matn tarkibiga mos kelishini ayting. Agar yo'q bo'lsa, ularni adashtiring.

1. There was only one atomic theory in the history of chemistry. 2. The light that is emitted by atoms of a given substance gives a distinctive pattern.3. The line spectrum is the spectrum of an atom but not a molecule. 4. The result of early investigations was that the line spectra of the hydrogen atom were not alike. 5. Niels Bohr was not interested in studying spectral lines. 6. The application of the quantum theory helped to understand the electronic structure of the hydrogen atom better.

Mashq 6. Matnda toping va rus tiliga tarjima qiling, bu erda biz chiziqli spesifikaning shakllanishi haqida gaplashamiz.

Section III
Ex. 1. Respond to the following requests and invitations. Use the expressions: with pleasure, here you are, certainly, ofcourse.

1. Shall We go to the University together? 2. Give me your textbook for some days, please. 3. Will you help me to do the exercise? 4. Please bring me my notebook, you’ll find it on the table. S. Let’s spend Sunday together. 6. Let’s go for a walk after finishing our homework. 7. Have you been to the Russian Museum? Let’s go there with Mary, she knows a lot about Russian art. S. Could you show me the way to the laboratory of organic chemistry, please?

Ex. 2. Translate the sentences into English.

1. Ertaga kinoga boramizmi? - Jonim bilan. 2. Iltimos, menga bir daqiqaga qalam berib turing. - Iltimos. 3. Kechqurun mening oldimga keling, men sizga bu kitobni beraman. - Jonim bilan. 4. Ertaga seminarga kelasizmi? - Albatta. 5. Siz adashdingiz, bu mening daftarim? - Mana ol. 6. Ertaga menga ushbu maqolani olib kelishni unutmang. - Albatta. 7. Iltimos, tajribamni tugatishga yordam bering. - Jonim bilan

Ex. 3. Make up short dialogues according to the model.

Ex. 4. Give detailed answers to the following questions:

1. What kind of particle is called an atom? 2. What was Dalton’s idea of an atom? 3. What is the difference between Dalton’s and modem theoryof the atomic structure? 4. In what way did Bohr’s work develop the atomic theory? 5. What relationship is there between an atom and its spectrum?
Ex. 5. Discuss the following topics:

1. The Evolution of the Atomic Theory.

2. The Modem Concept o f die Composition and Structure of an Atom.

3. The Basis for Spectral Analysis.

WHAT IS IT?

An optical instrument for forming and examining spectra.