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Class 10 Class 12

Is Matter Around Us Pure

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What are the Types of Pure Substances

On the basis of their chemical composition, substances can be classified either as elements or compounds.



Substances that is made up of one or more elements by chemical combination are called compounds, such as water, carbon dioxide, copper oxide, hydrochloric acid, etc. A compound does not contain the properties of its constituent elements and shows quite different characteristics.


1. The components of a mixture may be present in any ratio.


1. The components of a compound are always present in a fixed ratio by mass.

2. Mixture may be homogeneous or heterogeneous in nature.

2. Compounds are always homogeneous.

3. The components of a mixture can be easily separated by simple physical or chemical means.

3. The constituents (elements) of the compound cannot be separated either by physical or mechanical means. They can, however, be separated using heat or light (chemical means).

4. Components of the mixture can be easily seen with naked eye or with a magnifying glass.

4. Components of the compound can in no case be seen with naked eye or with a magnifying lens.

5. The properties of a mixture are midway between those of its constituents.

5. The properties of a compound are entirely different from those of its constituents.


Elements can be normally divided into metals, non-metals and metalloids.

Metals usually show some or all of the following properties:

  1. They have a lustre (shine).
  2. They have silvery-grey or golden-yellow colour.
  3. They conduct heat and electricity.
  4. They are ductile (can be drawn into wires).
  5. They are malleable (can be hammered into thin sheets).
  6. They are sonorous (make a ringing sound when hit).

Examples of metals are gold, silver, copper, iron, sodium, potassium etc. Mercury is the only metal that is liquid at room

Non-metals usually show some or all of the following properties:

  1. They display a variety of colours.
  2. They are poor conductors of heat and electricity.
  3. They are not lustrous, sonorous or malleable.

Examples of non-metals are hydrogen, oxygen, iodine, carbon (coal, coke), bromine, chlorine etc.

Some elements have intermediate properties between those of metals and non-metals, they are called metalloids; examples are boron, silicon, germanium etc.