Candidates can download NCERT Exemplar Class 8 Science Unit 4 from this page. The exemplar has been provided by the National Council of Educational Research & Training (NCERT) and the candidates can check it from below for free of cost. It contains objective, very short answer type, short answer type, and long answer type questions. Along with it, the answer for each question has also been provided. From the NCERT Exemplar Class 8 Science Unit 4, candidates can understand the level and type of questions that are asked in the exam.
NCERT Exemplar Class 8 Science Unit 4 Materials : Metals and Non-Metals
NCERT Class 8 Science Unit 4 is for Materials : Metals and Non-Metals. The type of questions that will be asked from NCERT Class 8 Science Unit 4 are displayed in the below provided NCERT Exemplar Class 8 Science Unit 4. With the help of it, candidates can prepare well for the examination.
Multiple Choice Questions
1. Which of the following is not a metal?
(a) copper
(b) sulphur
(c) aluminium
(d) iron
2. The substance that will be flattened on beating with a hammer is
(a) crystal of iodine
(b) lump of sulphur
(c) piece of coal
(d) zinc granule
3. Boojho has learnt that non-metals on beating with a hammer are generally broken into pieces. Which of the following is a non- metal?
(a) iron nail
(b) aluminium wire
(c) copper plate
(d) piece of coal
4. Materials which can be drawn into wires are called ductile. Which of the following is not a ductile material?
(a) silver
(b) copper
(c) sulphur
(d) aluminium
5. Metals are generally hard. Which of the following metals is an exception and can be cut with a knife?(a) iron
(b) sodium
(c) gold
(d) magnesium
6. Metals are generally solid. Which of the following metals is in the liquid state at room temperature?
(a) mercury
(b) silver
(c) aluminium
(d) sodium
7. Metals generally react with dilute acids to produce hydrogen gas. Which one of the following metals does not react with dilute hydrochloric acid?
(a) magnesium
(b) aluminium
(c) iron
(d) copper
8. Which of the following reacts with cold water vigorously?
(a) carbon
(b) sodium
(c) magnesium
(d) sulphur
9. The metal which produces hydrogen gas on reaction with dilute hydrochloric acid as well as sodium hydroxide solution is
(a) copper
(b) iron
(c) aluminium
(d) sodium
10. Which of the following non-metals reacts and catches fire on exposure to air?
(a) phosphorus
(b) nitrogen
(c) sulphur
(d) hydrogen
11. Generally metallic oxides are basic and non-metallic oxides are acidic in nature. Solution of which of the following oxides in water will change the colour of blue litmus to red?
(a) sulphur dioxide
(b) magnesium oxide
(c) iron oxide
(d) copper oxide
12. Which of the following property is not responsible for copper to be used as electrical conduction wires?
(a) ductility
(b) colour
(c) good conductor of electricity
(d) it is solid
Very Short Answer Type Questions
13. Name two soft metals which can be cut with a knife.
14. Which non-metal is essential for our life and all living beings inhale it during breathing?
15. Name two major non-metals which are present in fertilisers and enhance the growth of plants.
16. Which non-metal is used to disinfect water?
17. A purple coloured non-metal forms a brown solution in alcohol which is applied on wounds as an antiseptic. Name the non- metal.
18. Zinc sulphate forms a colourless solution in water. Will you observe any colour on adding copper turning in it?
19. Why are bells made of metals?
20. Which liquid metal is used for making thermometers?
21. Which of the following metals can displace the other two metals from their salt solutions?
zinc, iron, copper
Short Answer Type Questions
22. Paheli bought a statue made of copper. To her surprise it acquired a dull green coating after a couple of months. Explain the reason.
23. In Fig 4.1 you find that the bulb glows when an iron nail is placed between two ends of wire. Complete the following sentences on the bases of this fact.
(a) __________ is a metal.
(b) Metals are good __________ of electricity.
24. If in Fig. 4.1 iron nail is replaced by a wooden stick, will the bulb glow or not? Justify your answer.
25. Paheli prepared a blue coloured solution of copper sulphate in beaker A and placed an iron nail in it. Boojho prepared a yellowish green solution of ferrous sulphate in beaker B and placed a copper wire in it. What changes will they observe in the two beakers after an hour?
26. A doctor prescribed a tablet to a patient suffering from iron deficiency. The tablet does not look like iron. Explain.
27. Match the substances in Column A with their applications given in Column B.
Long Answer Type Questions
28. Some of the following statements are incorrect. Find the incorrect statements and correct them.
(a) The property of metals by virtue of which they can be drawn into wires is called ductility.
(b) Metals are good conductor of electricity but poor conductor of heat.
(c) Articles made of metals produce ringing sound when struck hard.
(d) Oxides of non-metals and metals are acidic in nature.(e) A less reactive metal replaces a more reactive metal from its salt solution in water.
29. Iron is more reactive than copper. Can you write an activity to show this?
30. Fill in the blanks to complete the following paragraph.
The name of the product formed in the reaction of sulphur and _____________ is sulphur dioxide gas. When sulphur dioxide is dissolved in_________________, sulphurous acid is formed. The sulphurous acid turns _____________ litmus paper to ____________. Generally oxides of __________ are acidic in nature. After completing the paragraph write two questions which you can raise on the basis of this information.
31. Find out the names of three metals and three non-metals from the box given as Fig 4.2.
32. Complete the crossword given in Fig. 4.3 with the help of the clues.
Across
1. Which is generally hard, ductile, malleable and sonorous.
2. A metal is called so it can be drawn into wires.
3. Metal bells are used because of this property.
Down
4. A metal generally used for making jewellery.
5. A metal which is liquid at room temperature.
6. A metal which reacts with acid as well as base to form
hydrogen gas.
7. Substances used to enhance the growth of plants.
8. Property by virtue of which metals can be beaten into thin
sheets.
Click here to download the NCERT Exemplar Class 8 Science Unit 4 Materials : Metals and Non-Metals.
Answers to Multiple Choice Questions
Mutiple Choice Questions
Very Short Answer Questions
13. (i) sodium (ii) potassium
14. oxygen gas
15. (i) nitrogen (ii) phosphorus
16. chlorine
17. iodine
18. No, because displacement reaction does not takes place.
19. Metals are sonorous.
20. Mercury
21. Zinc
Short Answer Questions
22. The green material is a mixture of copper hydroxide and copper carbonate formed due to reaction of copper with moist air (water, oxygen and carbon dioxide).
23. (a) iron (b) conductor
24. The bulb will not glow as wood is not a good conductor of electricity.
25. In beaker A, a reddish brown layer of copper will deposit on the iron nail and the blue coloured solution will become yellowish green. On the other hand, no change is observed in beaker B.
26. The tablet is not made of iron metal, instead it contains a salt of iron.
27. (a)-(iii), (b)-(iv), (c)-(i), (d)-(v), (e)-(ii).
Long Answer Questions
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