Class 8 Science : Metals and Non-Metals

Metals and Non metals

1).Ques. Differentiate between metals and non metals.

Ans. 

Metals	Non-Metals
1.       Metals are hard except  Sodium and                  potassium  which are soft.	1.       Non-Metals are generally soft except                       diamond is very hard.
2.       Metals are malleable and can be beaten             into thin sheets.	2.       Non-Metals are non- malleable and brittle.
3.       Metals are Ductile and can be drawn into               wires.	3.       Non-Metals are  non ductile.
4.       Metals are good conductors of heat.	4. Non-Metals are poor conductors of heat.
5.       Metals are good conductor of electricity.	5. Non- Metals are poor conductor of       electricity.

2) Ques.  Explain Malleability in Metals and Non-Metals.
Ans. The property of metals by which they can be beaten into thin sheets is called Malleability.
It is the property by which metals like silver is used to make silver foils for decorating food items and aluminium is used for making aluminium foils for storing food items & keep them warm.
Non-metals do not show this property, on beating non metals like coal or wood breakdown into small pieces.
so, we can say that Metals are malleable but non-metals are not malleable.

3) Ques. Explain the process of rusting of Iron.
Ans. The surface of some metals get corroded when exposed to moist air for long time, it is called corrosion. Rusting of Iron is an example of corrosion. The chemical equation for rusting of Iron is:
 2Fe   +     3/2 O2    ---->  Fe 2O3.x H2 O.

4) Ques. What are the noble metals?  and What are their uses? 
Ans. The Metals which retain their lustre because they do not  react with water, air or acids are called Noble Metals.

• Uses of Noble Metals:

1. Gold and silver are used for Making jewellery, ornanents , coins , medals , etc.
2. Metals like Platinium are used for making jewellery and electric gadgets, etc. 

5) Ques. What do you mean by Displacement Reaction?

Ans.  In a displacement reaction a more reactive metal get replaced by least reactive metal. Both Metals and non metals take part in chemical reaction.

For Example :- Reaction of Iron nails with Copper Sulphate solution.

6) Why there is a difference in dropping of a metal coin or a piece of coal?

Ans. The sound of a metal coin and a piece of coal is different because metals produce sound on ringing, and are called sonorous but Non metals do not show this property.