2015-08-21
1444
1. The electrons of the outer shell are called ….
2. Each valence electron orbits not only around the parent atom but also ….
3. … can easily give up valence electrons.
4. In a solid piece of pure silicon there are ….
5. … all the elements are grouped according to their chemical properties.
6. … is called a covalent bond.
7. Elements with similar properties are placed ….
8. … are relatively rare.
9. Some elements do not exist at all in Nature, they are ….
10. In each atom, having many electrons, there is ….
16. Study the text and translate the following:
· все элементы сгруппированы по их химическим свойствам
· элементы со схожими свойствами
· некоторые из элементов существуют в больших количествах
· некоторые элементы вообще не существуют в природе
· некоторые элементы создаются физиками-атомщиками
· специальное оборудование
· валентные электроны
· электроны внешней оболочки атома
· твёрдый кусок чистого кремния
· каждый валентный электрон вращается вокруг исходного атома
17. Match the terms in Table A with their definitions in Table B.
| Table A | Table B |
| 1. concentration 2. absorption 3. equipment 4. impurity 5. resistance | a. A process in which something takes in liquid, gas, or heat. b. The ability of a substance to stop the flow of an electric current through it. c. The amount of a substance contained in a liquid. d. The tools, machines, clothes etc that you need to do a particular job or activity. e. A substance of a low quality that is contained in or mixed with something else, making it less pure. |
SPEAKING
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Summarize the text “Covalent Bonds” in 150 words.
In pairs ask and answer text-based questions.
For example:
· How many elements are known to science today?
· Do you know that some elements do not exist at all in nature?
· How can we define valence electrons?
· And what if we consider atoms in a solid piece of pure silicon?
20. Divide into 2 groups. Group 1 translates Extract A and group 2 – extract B of the text “Semiconductors” with a dictionary in writing.
