Matter, Elements and Atoms

Matter consists of one or more elements.

Elements are substances that cannot be divided into other substances.

An atom is the smallest particle of an element, which has all the properties of the element and can take part in chemical reactions.

In each atom there is a nucleus containing a number of protons (each proton has a positive electrical charge) and a number of neutrons, having no electrical charge. The nucleus is surrounded by a number of electrons. Each electron has a negative electrical charge. The electrons orbit around the nucleus. An atom has as many protons as it has electrons. This results in a zero electrical charge of the atom. Electrons orbit around the nucleus in one of the several possible orbits. These orbits are called shells.

In a silicon atom there are fourteen protons in the nucleus. Fourteen electrons orbit around the nucleus in three orbits. The first or inner shell contains two electrons and cannot hold any more electrons. In the second shell there are eight electrons. It cannot hold additional electrons either (также). In the third shell there are only four electrons. This shell can hold more electrons. The outer shell of any atom is called its valence shell. The number of electrons in the valence shell is known as the valency of the atom.

15. Read the text again and complete the sentences.

1. In each atom there is ….

2. … is known as the valency of the atom.

3. An atom is the smallest particle of an element, which ….

4. The nucleus is surrounded by ….

5. The outer shell of any atom is called ….

6. An atom has as many protons as ….

7. In a silicon atom there are ….

8. … are substances that cannot be divided into other substances.

9. … orbit around the nucleus in one of the several possible orbits.

Match the terms in Table A with their definitions in Table B

Table A

1. matter

2. atom

3. proton

4. nucleus

5. valency

Table B

a. The smallest part of an element that can exist alone or can combine with other substances to form a molecule.

b. The material that everything in the universe is made of, including solids, liquids and gases.

c. The central part of an atom, made up of neutrons, protons and other elementary particles.

d. A very small piece of matter with a positive electrical charge that is in the central part of an atom.

e. A measure of the power of atoms to combine together to form compounds.

Speaking

17. Summarize the text ‘ Matter, Elements and Atoms’ in 150 words.

You are taking your exam in Physics. Your examination card says: Matter, its definition and basic notions. Your partner is your examiner. Answer his questions and try to get a good mark.

You may begin like this: -Well, what is matter?

Your partner: - Matter is …

19. Divide into 2 groups. Group 1 translates Extract A and group 2 – extract B of the text “Electricity” with a dictionary in writing, paying attention to the use of the Past Simple.

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