Class 8 Material Metals and Non Metals Extra Question Answer

Class 8 Material Metals and Non-Metals Extra Question Answer

Define the following terms

 

Malleability: –

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

 

Ductility: –

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

 

Sonorous: –

Property of metals that produces ringing sounds on hitting. The ringing property of metal depends on temperature and density.

 

Rust: –

Iron reacts with the oxygen present in air and moisture and forms hydrated iron (III) oxide which is known as rust and the process is known as rusting of iron.

Element: –

The substance that cannot be broken down into two (or more) simpler substances by chemical reactions (by applying heat, light, or electricity) is called an element.

 

Metalloids: –

The elements whose properties are intermediate between those of metals and non-metals are known as metalloids. Examples of metalloids are Silicon, Germanium, Arsenic, and Tellurium.

 

Brittleness: –

The property due to which non-metals break on hammering is called brittleness.

 

Why sodium metal is kept in kerosene?

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.

 

How Iron is present in our body?

In our body, iron is present in the pigment of red blood cells called ‘hemoglobin’ (which transports oxygen from the lungs to all the tissues of our body).

 

List some characteristics of Metals?

The characteristics of metals are:-

  • Metals are malleable and ductile elements
  • Good conductors of heat and electricity
  • Metals are lustrous or shiny
  • Metals are usually hard and strong.
  • Metals have high melting points and boiling points
  • Metals have high densities which means they are heavy
  • Metals are sonorous which means producing sound when struck.

 

List some characteristics of Non-Metals?

The characteristics of non-metals are:-

  • They are neither malleable nor ductile
  • They are brittle in nature
  • They are do not conduct heat and electricity
  • They are not lustrous or shiny
  • They are neither hard nor strong.
  • Non-metals have low densities which mean lightweight
  • Non-metals are not sonorous [do not produce any sound when struck]

 

Answer in 1 or 2 words.

 

Which metals are used in making electric wires?

Copper and aluminum.

 

Which metals are used in making utensils?

Copper, aluminum, and iron.

 

Which metals are used in thermometers?

Mercury.

 

Which metals are used in making jewelry?

Gold and silver.

 

Which metals are used in making fertilizers?

Phosphorus.

 

What happens when a metal reacts with oxygen. write down the reaction.

Metal + oxygen = metal oxide

Magnesium + Oxygen = Magnesium Oxide  [Mg + O2 = Mgo]

 

 

The smallest particle of an element is called an ‘atom’.

An element is a substance that is made up of only one kind of atom.

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