3 Part One. The Predicate

Chemical Symbols for Elements
The Swedish chemist Berzelius (1779-1848) introduced the modem symbols for the elements when he published a list of “atomic weights" in 1818. Those elements which, on account of their case of extraction from their ores had been known from prehistoric times, were given symbols derived from their Latin names.

The symbols began as a simple shorthand for referring to the names of the elements, but rapidly acquired a quantitative significance. Pb began meaning “some lead”, but it rapidly changed and came to mean cither “one atom of lead” or “one gram atomic weight of lead”, i. e. 207 g of lead.

Some elements can exhibit allotropy; that is to say, they can exist in two different forms in the same physical state. Taking examples from among gaseous elements, ozone and molecular oxygen both contain only oxygen atoms, yet, the reactions of ozone are completely different from those of oxygen. It will immediately oxidize rubber and metallic silver, whereas oxygen will do neither. Evidence from gas-volume determinations shows that three atoms of oxygen are associated in ozone, whereas there are only two atoms in molecular oxygen. The atoms of all common gaseous elements exist in pairs except the inert gases. To avoid confusion, molecular gases are written O₂, N₂, Cl₂ and ozone O₃.

Some elements also exhibit allotropy; for example, white phosphorus catches fire in air at room temperature while red phosphorus is stable in air at 240°C. But since there is no way of discovering how many atoms are combined together in any solid, the question is sidestepped, and all solid elements including allotropcs are given symbols; thus, both white and red phosphorus are P rather than P_x.

Words and Word-Combinations to Be Memorized

on account of, associate, avoid, come + миф., completely, confusion, gaseous, either... or..., except, exist, extraction, include, introduce, list, molecular, neither, quantitative, rapidly, rather than, refer to, rubber, since, solid, stable, symbol, volume, yet

Ex. 6. Give th e Russian equivalents fo r th e following:

introduce smth., a list of “atomic weights”, on account of, refer to the names of the elements, acquire a quantitative significance, cither... or..., exhibit allotropy, that is to say, exist in different forms, in the same physical state, take an example, from among gaseous elements, yet, be completely different, whereas, exist in pairs, avoid confusion, for example, catch fire in air, there is no way of, both... and..., rather than

Ex. 7. Give th e English equivalents for the following:

kimyoviy belgi, shved kimyogari, chunki (asoslangan), tarixdan oldin, tez, yoki ... yoki ... ham (har qanday mulk), xuddi shu holatda, misol keltiring, ikkalasi ham ... kabi. ... va ... ammo, masalan, masalan, xona haroratida havoda olov yoqilishi, qancha, shuning uchun ...

Ex. 8. Fill in th e b lan k s w ith prepositions w h ere n ecessary .

in, at, of, except, from , for, on account of

1. Berzelius introduced the modern symbols... the elements... 1818.2. Some elements had been known ... prehistoric times ... their ease ...extraction. 3. The symbols ... these elements were derived ... their Latin names. 4. There are elements which can exist... two different forms ... the same physical state. 5. Reactions... ozone are completely different... those ... oxygen. 6. White phosphorus catches fire ... air ... room temperature. 7. The atoms... all common gaseous elements exist... pairs ... the inert gases.

Ex. 9. Supply the definite or indefinite article.

1. Mendeleyev is ... famous Russian chemist. 2. Mendeleyev is ...founder of the Periodic Law. 3. Professor N is ... author o f a great number of papers and books. 4. Swedish chemist Berzelius was... great discoverer.5. Do you know who ... discoverer of the atomic theoiy was? 6. Niels Bohr was ... Danish physicist. 7. Chemistry is ... branch o f knowledge. 8. Section II is concerned with ... nature of radioactivity. 9. Dr. N dis­covered ... new law. 10. Faraday was ... well-known English physicist.

Ex. 10. Translate the sentences into Uzbek, paying attention to the predicates.

1. Chemistry concerns the compositions of matter and theirtransformations. 2. A great number of Russian scientists, among them Mendeleyev, Lomonosov, Butlerov et al., could be mentioned ascontributors to the world science. 3. There are several fields o f chemistry in which Russian scientists have achieved significant progress. 4. The Periodic Law laid the foundation for the modem development of chemistry.5. In the molten state metals are able to interact with one another. 6. Alloys which contain only two metals are referred to as bimetallic. 7. Science has become an important part of the modem world. 8. Chemists are needed almost in every field of life. 9. The theories and laws of chemistry are no less exact as those of physics. 10. Silicon, the fourteenth element in the periodic table might be called a congener o f carbon, in Group IV.11. Attempts to arrange the elements in a definite order were followed by a great discovery, the discovery of the Periodic Law. 12. The periodic tabic may be interpreted in terms of electronic structure o f atoms. .13. Radioactivity was discovered by Henry Becqucrcl in 1896. 14. The change o f the program of experimentation could have given more accurate results. 15. Before definite chemical evidence for the compound nature of a substance was obtained, the substance had been considered an clement.16. In 1903 scientists recognized that radioactivity involves the spontaneous transmutation of elements. 17. Here We are going to give a detailed account of this phenomenon. 18. Heating was to have an important influence on the rate of the reaction. 19. Two points should have been determined: the composition of the sample and the relative weights of its constituent parts.20. The result of the comparison may be completely the opposite. 21. The next step was to arrange the data in a table. 22. At any given temperature a molecule of a light gas such as helium or hydrogen will have the same average kinetic energy. 23. Chemists must have known a great number ofreactions that can procccd without catalysts. 24. Few chemical reactions involve just a single elementary process. 25. We have prevented the formation of by-products. 26. New methods of investigation are being developed, they are much more effective than the older ones.

Ex. 11. Translate the sentcnccs into English.

1. 1818 yilda Bersilius "atomlarning barchasi" ro'yxatini e'lon qildi. 2.Berzelius kimyoviy elementlarning zamonaviy belgilarini kiritdi. 3.Ba'zi elementlar bir xil fizik holatda ikki xil shaklda mavjud bo'lishi mumkin. 4. Ozon ham, molekulyar kislorod ham faqat kislorod atomlaridan iborat. 5. Ozon reaktsiyalari kislorod reaktsiyalaridan mutlaqo farq qiladi. 6. Ozon uchta kislorod atomiga, molekulyar kislorod ikkitaga ega. 7. Chalkashmaslik uchun gaz molekulalari O₂, N₂ va hokazo kabi yoziladi. 8. Qizil fosfor havoda 240 ° C haroratda turg'undir. 9. Oq fosfor, masalan, xona haroratida havoda yonadi.

Ex. 12. Make up questions to the italicized parts of the sentences.

1. The symbolsbegan as a simple shorthandfor referring to the namesof the elements (3). 2. Ozone will immediately oxidizemetallic silver(3).3. There is no way of discovering how many atomsare combined together in any solid(2).

Ex. 13. Answer the following questions:

1. What were the symbols introduced for? 2. Who introduced the symbols for chemical elements and when did he do it? 3. What significance did symbols acquire? 4. What is the difference in writing allotropic modifications of elements?