SCHOOL SECTION 173

Understanding Metalsand Non Metals8.

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SCHOOL SECTION174

Q.I (A) Fill in the blanks :

1. ....................... element that has the highest melting point.

2. ....................... is the only non-metal in liquid state.

3. Chocolates are wrapped in an aluminium foil, this is an application of

property of ....................... .

4. PVC stands for....................... .

5. Metal oxides are usually ....................... in nature.

6. Aluminium oxide is ....................... in nature.

7. Metals react with water to form a metal hydroxide and ....................... gas

is liberated.

8. Metals react with dilute acids to give ....................... and .......................

gas is liberated.

9. Sodium is a ....................... coloured metal.

10. Chlorine is a ....................... .

11. The most unreactive metals i.e. which are not affected by air and water

e.g. silver, gold and platinum are generally found in ....................... state.

12. The symbol of Aluminium is ....................... .

13. The valency of aluminium is ....................... .

14. Aluminum undergoes an oxidation reaction forming a thin layer of

....................... .

15. Potassium is the ....................... metal.

16. Pure gold is ....................... gold.

17. Pure gold is alloyed with ....................... or ....................... to make

ornaments.

18. Aqua regia can dissolve metals like....................... and ....................... .

Answers :

1. Tungsten 2. Bromine

3. malleability 4. poly vinyl chloride

5. basic 6. amphoteric

7. hydrogen 8. salt and hydrogen gas

9. silver 10. non-metal

11. free or native 12. Al

13. 3 14. aluminium oxide

15. most reactive 16. 24 karat

17. silver or copper 18. gold and platinum.

Q.I (B) Match the following :

1. Column I Column II

(i) Malleability (a) Silver, copper

(ii) Ductility (b) Hammered to sheets

(iii) Sonorous (c) Drawn into thin wires

(iv) Good conductors (d) Bells in schools, churches

Ans. (i - b), (ii - c), (iii - d), (iv - a).

2. Column I Column II

(i) Sodium meta aluminate (a) NaAlO2 or Na2Al2O4

(ii) Sodium oxide (b) Ca(OH)2

(iii) Calcium hydroxide (c) Na2O

(iv) Copper sulphate (d) CuSO4

Ans. (i - a), (ii - c), (iii - b), (iv - d).

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SCHOOL SECTION 175

3. Column I Column II

(i) Potassium (a) greenish yellow poisonous gas

(ii) Sodium (b) Ionic bond

(iii) Chlorine (c) Na

(iv) NaCl (d) Most reactive element

Ans. (i - d), (ii - c), (iii - a), (iv - b).

4. Column I Column II

(i) Metals (a) Negative ions

(ii) Cations (b) Brittle

(iii) Non-metals (c) Positive ions

(iv) Anions (d) Lustre

Ans. (i - d), (ii - c), (iii - b), (iv - a).

Q.I (C) State whether the following statements are true or false. If false

write the corrected statement :

1. Silver is the best conductor of electricity and next in order is copper.

Ans. True.

2. PVC is a bad conductor of electricity.

Ans. True.

3. Aluminium is a non-metal.

Ans. False. Aluminium is a metal.

4. Almost all metals react with oxygen to form metal oxide, but the reactivity

differs for different metals.

Ans. True.

5. Most metal oxides are insoluble in water.

Ans. True.

6. Metal oxides dissolve in water to form alkalis.

Ans. True.

7. In anodizing technique, a thin film of aluminium oxide is formed on surface

of cathode.

Ans. False. In anodizing technique, a thin film of aluminium oxide is formed on

surface of anode.

8. Silver and gold react with dilute acids.

Ans. False. Silver and gold do not react with dilute acids.

9. Chlorine is a greenish coloured poisonous gas that was used as a weapon

during World War I.

Ans. True.

10. Most metals however are found in combined state in the form of their

oxide ores, carbonate ores, or sulphide ores.

Ans. True.

Q.I (D) Find the odd man out :

1. Copper, Silver, Iron, Plastic.

Ans. Plastic as rest all are good conductors.

2. Malleability, Ductility, Brittleness, Lustre.

Ans. Brittleness, it is the physical property of a non-metal while rest are physical

properties of metals.

3. Steel, Iron, Copper, Tungsten.

Ans. Steel as it is an alloy, rest are elements.

4. Bauxite, Cinnabar, zinc carbonate, Hydrogen.

Ans. Hydrogen as rest are ores of metals.

5. K2O, Na2O, Al2O3, CaO.

Ans. Al2O3 as it is an amphoteric oxide while rest are basic oxides.