METALS AND NON-METALS

There are 105 elements in the Mendeleyev's Periodic System. These elements are divided into two groups: the metals and the non-metals. Here is a table showing the difference (таблица, показывающая различия) between metals and non-metals.

Physical properties of metals:

1. Solid at room temperature (mercury is the only liquid metal).

2. Have a high density (except potassium and sodium).

3. Can be moulded by pressure, that is they are malleable.

4. Have high melting and boiling points.

5. Can be drawn into wire, i.e. (that is) they are ductile.

Physical properties of non-metals:

1. Many are liquids and gases at room temperature.

2. Density is usually low.

3. Solid non-metals are brittle.

4. Have low melting and boiling points.

5. Cannot be drawn into wire.

Chemical properties of metals:

1. Have basic oxides.

2. React with dilute acids forming salts.

3. Form positive ions.

4. Are liberated at the cathode during electrolysis.

Chemical properties of non- metals:

1. Have acidic oxides.

2. Salts of non-metals do not exist.

3. Form negative ions.

4. Are liberated at the anode during electrolysis.

4. Найдите в тексте ответы на следующие вопросы

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?

Заполните пропуски следующими подходящими по смыслу словами: 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. Прочтите предложения и укажите, какие из данных утверждений верны или неверны ("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. Прочтите еще раз внимательно текст "Metals and Non-metals". Постарайтесь ответить по-английски на вопросы, не заглядывая в текст

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?

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