CBSE – 8th Standard Science

Question Bank – Chapter 4 – Metals and Non Metals

CHAPTER 4 

MATERIALS: METALS AND NON-METALS

 

Qus 1. What is malleability?

Ans. The property of metals by which they can be beaten into thin sheets is called malleability.

 

Qus 2. How rust is formed?

Ans. Rust formed by the reaction between iron, oxygen and water.

 

Qus 3. What do you mean by ductility?

Ans. The property of metal by which it can be drawn into wires is called ductility.

 

Qus 4. Why metals are said to be sonorous?

Ans. Metals produce ringing sounds and that is why they are said to be sonorous.

 

Qus 5. What are metals?

Ans. The materials which are hard, lustrous, malleable, ductile, sonorous and good conductors of heat and electricity are called metals.

 

 

Qus 6. Give some examples of metals?

Ans. Iron, copper, aluminium, calcium, magnesium, etc are some of the examples of metals.

 

 

Qus 7. What are non-metals?

Ans. Materials which are not sonorous and are poor conductors of heat and electricity are called non-metals.  

 

Qus 8. Which is the only metal found in liquid state at room temperature?

Ans. Mercury is the only metal which is found in liquid state at room.

 

 

Qus9. Explain the term ‘Exceptions’?

Ans. Metals like sodium and potassium are soft and can be cut with a knife whereas Mercury is the only metal which is found in liquid state at room temperature. These are exceptions.

 

Qus 10. Why sodium metal is always stored in kerosene?

Ans. Sodium metal is very reactive. It reacts vigorously with oxygen and water. A lot of heat is generated in the reaction. It is, therefore, stored in kerosene.

 

Qus 11. Why phosphorus is stored in water?

Ans. Phosphorus is a very reactive non-metal. It catches fire if exposed to air, to prevent the contact of phosphorus with atmospheric oxygen, it is stored in water.

 

Qus 12. What is an element?

Ans. When a substance cannot be broken down further by chemical reactions, by cooling, heating, or by electrolysis, it is called ‘element’.

 

Qus 13. What does ‘pop’ sound indicates when metal react with acids?

Ans. The ‘pop’ sound indicates the presence of hydrogen gas.

  

Qus 14. Write some uses of non-metals?

Ans. Non-metals are used fertilisers, water purification process, antiseptic and crackers.

 

Qus 15. What is the smallest unit of an element?

Ans. The smallest unit of an element is atom .

 

 

TRY THESE :-

 

Q.1 Give an example of metal which:

(i) Is liquid at room temperature

(ii) Can be easily cut with knife

(ii) is the best conductor of heat and electricity.

 

Q 2.  Explain why, Zinc metal can displace copper from copper sulphate solution but copper cannot displace zinc from zinc sulphate solution

Q.3  Why GOLD is preferred in making jewellery?

 

Q.4   What happens when iron reacts with oxygen and water? Give the chemical reaction involved.

 

Q.5  What happens when iron nails are put in copper sulphate solution?

 

CBSE 8th Standard Science

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CBSE 8th Standard Science Syllabus and Revision Notes

  • Crop Production & Management
  • Microorganisms – Friends & Foe
  • Synthetic, Fibers & Plastic
  • Materials – Metals & Non-Metals
  • Coal & Petroleum
  • Combustion & Flame
  • Conservation Of Plants And Animals
  • Cell Structure And Functions
  • Reproduction In Animals
  • Reaching The Age Of Adolescence
  • Force And Pressure
  • Friction
  • Sound
  • Chemical Effects Of Electric Current
  • Some Natural Phenomena
  • Light
  • Stars And The Solar System
  • Pollution Of Air And Water