Answer the following questions using information given in Text A.
1) По каким двум основным совокупностям свойств мы делим химические элементы на металлы и неметаллы?
2) Каковы отличия металлов от неметаллов на основании физических свойств?
3) Каковы отличия металлов от неметаллов на основании химических свойств?
4) Какие свойства элементов имеют большее значение для отнесения того или иного элемента к металлам или неметаллам? Поясните Ваш ответ примерами из текста.
5) Сколько элементов таблицы Менделеева относятся к металлам?
5. Fill in the blanks with the following words: good, poor, sodium, salts, cathode, anode, high, ductile, positive, negative, malleable, brittle, graphite, mercury, potassium.
1) All metals are solid at room temperature except … .
2) Metals have a high density except … .
3) Non-metals are poor conductor of electricity except … .
4) Solid non-metals are ... while metals are … .
5) Metals always form ... ions while non-metals form ... ions.
6) When metals react with acids in result ... are formed.
7) During electrolysis metals are liberated at the ... while non-metals are liberated at the … .
8) Metals have ... melting points.
9) Metals are ... conductors of heat and electricity while non-metals are ... conductors of heat and electricity.
10) Metals can be drawn into wire, that is they are … .
6. Read and decide if the following statements are right or wrong. ("That's right"; "That's wrong").
1) All metals are solid at room temperature.
2) Non-metals usually have low density.
3) All non-metals are poor conductors of heat and electricity.
4) Non-metals react with dilute acids forming salts.
5) Metals form positive ions.
6) These positive ions are liberated at the anode during electrolysis.
7) Non-metals can be drawn into wire.
8) Not all metals have a high density.
9) Metals have high-melting points.
10) Graphite is a metal.
11) Potassium and sodium have a high density.
12) Most metals are liquid at room temperature.
13) Solid non-metals are brittle.
14) Physical properties are much more important for deciding whether this or that element is a metal or a non-metal.
7. Read again the text "Metals and Non-metals". Answer the following questions without looking into the text.
1) How many elements are there in the Mendeleyev's Periodic Таble?
2) What groups are these elements divided into?
3) What are the main differences between metals and non-metals:
- on the basis of their physical properties;
- on the basis of their chemical properties?
4) How many elements are considered to be metals?
5) What properties (physical or chemical) are much more important for deciding whether this or that element is a metal or non-metal?
Independent tasks
8. Write down all new words and phrases in your notebooks. Group them into sections: nouns, adjectives, verbs, and phrases. Learn these words and phrases for the next lesson.
Read additional texts about metals and retell them in Russian.
GOLD
It is supposed (полагают) that gold was the first of all metals used by man. Why did the ancient people want gold? They did not use it аs money. Other things had served for money long before gold was used. Most likely, they wanted gold only for ornaments (украшения). Gold is a wonderful metal in many ways. As you know, gold is a yellow metal, bright and shining when polished – the colour of the sun. Perhaps, gold seemed to the ancient people to be a piece of the sun found on the earth and all ancient gold – seeking people (золотоискатели) were worshippers (поклонниками) of the sun.
COPPER
Copper came after gold. Then came tin, lead, silver and iron. We know that copper and tin came into use some time before silver and lead and a long time before iron. Probably, it was in Egypt that man first found copper. In ancient times copper was used in the form of alloys-bronze and brass. As we know, an alloy is a mixture of two or more metals. Bronze is a mixcture of copper and tin. Brass is an alloy of copper and zinc (цинк). Sometimes silver is added to bronze when bells are cast (отливать колокола). It is believed that silver gives a clear tone. Throughout (за всю) history of the world copper and bronze have always been used for making works of art (произведение искусства).
LESSON 3
CLASSIFICATION OF METALS