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THE PERIODIC TABLE OF D.I. MENDELEYEV
There are certain natural groupings among the chemical elements in which every element is closely related to the other elements in its group. In order to understand better these groupings, chemists have tried to fit the elements into a single plan. One of the earlier attempts to fit the relationships among the elements into a single law was made by John Newlands in England, who suggested the Law of Octaves. This concept of the periodic repetition of properties was further developed by a Russian chemist Dmitri Mendeleyev who created a Periodic Table in which he arranged the elements according to their atomic weights and corresponding chemical properties. D.I. Mendeleyev listed the elements known at the time (1869) in the order of their atomic weights from the lightest to the heaviest. The elements were arranged in a table of eight columns; elements having similar properties appeared in the same columns or groups in the table. Mendeleyev even predicted that there were undiscovered elements and left empty spaces in this table for the new discoveries.
There are many ways the Periodic Table can be used. The table can be used to find the atomic number. The atomic weight is also indicated in the table. The orbital arrangement of electrons is shown for each of the elements. The common oxidation states are given. For most elements these numbers are the same as the valence numbers. The table enables us to recognize6 families of elements. For example, copper (29), silver (47), and gold (79) will all be found in the same column. They have similar properties and are considered a chemical family. And at last the table can be used to predict the properties of the elements. The fact that the Periodic Table can assist in predicting properties of elements has helped in the discovery of missing elements.
|arrange– розташовувати list- перелічувати assist- сприяти predict -передбачати certain- визначений relate – зв’язувати closely - близько||repetition - повторення common - загальний show- демонструвати concept - концепція, поняття single -одиничний indicate -вказувати suggest - припускати|
1. What certain natural groupings are there among the chemical elements?
2. What have chemists tried to do in order to understand better these groupings?
3. Who made one of the first attempts to fit the relationships among the elements?
4. Who developed the concept of the periodic repetition of properties?
5. What columns are there in the Periodic Table?
6. What did Mendeleyev predict?
7. What are the ways the Periodic Table can be used?
Dates Ordinal numbers Cardinal numbers Exercise 5. Write down the following in figures.1. twenty-five million seven hundred thirty-two thousand 2. ten million five hundred sixty-seven thousand five hundred fifty-two 3. two million one hundred fifty thousand one hundred thirty-one 4. one million six hundred eighty-two thousand twelve 5. one point three million 6. sixty-seven thousand and five 7. two hundred thousand ninety-five 8. forty-five... [читать подробенее]
1. Exercise 2. Have a look at the adverbs in bolt. Find them in the UNIT and guess their meaning. Read the quotations and translate them. Exercise 1. Find the Russian equivalent. 1. to indulge in 2. to prefer 3. to introduce 4. to expect 5. to proffer 6. to squeeze 7. to exchange 8. to gain A. расценивать B. выражать C. предлагать D. приобретать E. кричать F. следовать G. избегать H.... [читать подробенее]
Ex. 59. Complete the following sentences about the important moments in history using the Past Continuous form of the verbs in brackets. Ex. 58Read the story and rewrite it in the past tense. Ex.57 Using the Past Continuous tense, fill in the blanks with the correct forms of the verbs shown in brackets. Ex.56 Using the Past Continuous tense, fill in the blanks with the correct forms of the verbs shown in brackets. Then rewrite the following affirmative statements as questions... [читать подробенее]
Ex. 48. Explain the use of the Simple Past in the following sentences. The First TV Soap Opera Ex. 47. Put the verbs in brackets into the Past Simple. The first TV soap opera (a) ……….. (appear) on American television just after the Second World War. Its name (b) ………. (be) Faraway Hill and it (c) ……….. (begin) on the 2nd of October, 1946. A famous Broadway actress, Flora Campbell, (d) ………… (play) Karen St. John, a rich New York woman who (e) ……….... [читать подробенее]
EQUITY In a general sense equity means fairness. In English law, equity means that body of rules originally enforced only by the Court of Chancery. Equity has been described as “a gloss (meaning a supplement) on the common law”, filling in the gaps and making the English legal system more complete. Petitions from persons unable to obtain justice in the common law courts were sent to the King as “fountain of justice”. These petitions were sometimes examined by the King and Council... [читать подробенее]
Task 12. Fill in the blanks. Task 11. Guess the meaning of the international words using in the text. Task 10. Make up the questions. SUBMISSION SEAT 1) something to sitting on, e.g. a chair 2) a place where something is, or is located or based 3) a parliamentary constituency 4) membership in legislative body1) act of accepting the power or authority of another 2) legal theory, opinion presented to a judge or jury 3) the act of presenting something, e.g. a... [читать подробенее]
Task 10. Make up sentences using the following expressions. Judicial branch, according to, the highest tribunal, Chief Justice, to be appointed by, to be approved by, to alter, successful experience, to pass laws, to be authorized, principal duty, to be at stake. 1. What responsibility does the judicial branch have? 2. What kind of court is the judicial power vested in according to the Constitution? 3. Could you describe the Supreme Court of the USA? 4. What do you know about the... [читать подробенее]
Part two Discuss the following before you listen. You will hear an interview with Tim Rice, who wrote the lyrics for Part one The writerJesus Christ Superstar. It was first performed in the 1970s, but hasn’t been performed many times since. Andrew Lloyd Webber composed the music. a) What are some of the main events in the life of Jesus Christ? Who were some of the main characters in his life? b) Why do you think Tim Rice and Andrew Lloyd... [читать подробенее]
Ex. 3. Read and translate the text. The Randolf sisters, Sadie and Esther, live just a block away from each other. Sadie constantly complains that the people in town are cold and unfriendly, while Esther finds them warm and pleasant. Although Sadie can’t see it, the difference is in the way they approach those people. Sadie and her husband have a lovely house. It’s filled with beautiful antique furniture and glassware that is so fragile it could easily be broken by a careless guest... [читать подробенее]
Discussion Ex. 1. Read and translate the text. Ex. 2.Work in pairs. Ex. 1. Answer the questions. Discussion 1. What are the three types of housing mentioned? 2. What is the ratio of houses to flats in Britain? 3. What has happened to home ownership in Britain? 4. What sort of people in the UK are most and least likely to own their houses? 5. Explain the following: sheltered housing, a mortgage, a slum area.1. What differences are there between housing in... [читать подробенее]