Fill in the table

2. Read and translate the following international words:

Nouns (n): crystal, group, helium, radiation, radium, valence, uranium.

Adjectives (adj): central, covalent, cubic, periodic, vertical, economic(al).

Verbs (v): group, radiate, vibrate.

3. Read the dialogue and learn how to speak about your past activities. Put the verb in brackets into the Past Continuous. Pay attention to the terms of electricity.

Peter: Hi, Paul. Glad to see you.

Paul: So am I. Peter, can you tell me what you (to do) yesterday from 9 till 11 a.m.? I (to look for) you.

Peter: Well, let me see. A few students and I (to carry out) some experiments with different electrical devices. As for me, I (to measure) the voltage.

Paul: And what about Alex? Do you happen to know what he (to do)?

Peter: As far as I remember, he (to measure) the resistance of a lead.

Paul: Oh, I see. I hope Michael (to help) him.

Peter: Yes, he was. He (to connect) leads to the multimeter. The needle (to indicate) the value of the resistance on the scale.

4. Put in the missing words, using the words from the table above:

1. Last year we were solving the problem of how to dispose of … waste.

2. Plants … oxygen.

3. The energetic flow circulates in harmony with the rhythm of its ….

4. Silicon is the material of which most semiconductors are ….

5. Darker surfaces … heat.

6. … passes quickly through materials such as metals.

7. Elements with … properties are placed in the same vertical column.

8. Some elements are created by atomic physicists using special ….

9. In the crystal … each atom employs its four valence electrons to form covalent … with four neighbouring atoms.

10. In its solid … silicon forms crystals of the diamond type.