Read the text. While translating pay special attention to the Participles.

ELEMENTS

There is a limited number of chemical elements, however, these elements can compose all the materials found on the earth. Each of them is very important. Some of the elements are very common, others are rare. There are elements never seen in pure form by most chemists as they are so rare.

Elements have properties distinguishing them from other substances.

Some of these properties are their colour, hardness, odour, taste, density, elasticity, flexibility, solubility in water or other liquids, their ability to conduct electricity, thermal conductivity and others. All these properties can help to distinguish one element from another.

For example oxygen is a colourless, odourless, tasteless gas. When combined with hydrogen of the air it burns. Argon is a noble gas. Helium being the most important of the inert gases is the lightest element except for hydrogen. Titanium located all over the world is light-weight, strong and corrosion-resistant. Iron being one of the most common metals is a good electricity and heat conductor.

D. I. Mendeleev is the scientist known by all chemists due to the table comprising elements arranged according to a definite system. This arrangement of elements often referred to by chemists is of great importance to science.

Notes to the text:

according to– согласно, соответственно

due to– благодаря

Read about hydrogen and characterize this element briefly.

Hydrogen

This substance occurring on the earth and in the sun and stars is the first element of the Periodic Table. Under normal conditions it is a colourless, odourless, tasteless gas. Hydrogen burning in the air must form water in a combination with oxygen. As water hydrogen is everywhere. This element, forming water, is a part of all acids and hydrocarbons. It is also a comprising part of vegetable and animal matter. We can get hydrogen bythe electrolysis of water, the steam-iron process,the steam-water gas process.

Notes to the text:

condition– условие

hydrocarbon – углеводород

occur- встречаться, попадаться

11. Analyze the "ing"-forms and translate the sentences into Russian:

1. Steel containing some metallic element other than iron and carbon is generally known as "special steel". 2. Mercury may be purified by washing it with dilute nitric acid. 3. They were using this substance in their experiment sev­eral times. 4. While examining the properties of this metal pay attention to its melting point. 5. Upon being heated he oxide changes into the red modification. 6. Being lower than hydrogen in the activity, mercury does not dis­place hydrogen from solutions of the acids.

12. Open the brackets choosing the correct form of the Participles:

1.The investigation (followed/following) by many experiments was of great importance. 2. The work (doing/done) by these researchers resulted to many new discoveries. 3. The nuclei (formed/forming) in this reaction are unstable. 4 The man (speaking/spoken) was the first who discover this phenomenon. 5. When (asking/asked) about this work/ he couldn’t answer anything. 6. Carbon (uncombined/uncombining) is a solid. 7. The man (experimented/experimenting) in that lab is our analyst. 8. The substance (experimented/experimenting) upon is an oxide.

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