Page 211 - New Medley 5 Semester 2

Classification of Matter

Matter can be classi ed into elements, compounds and mixtures depending
upon the nature of atoms present in it.

Elements

Some substances are made up of only one kind of atoms. Such a matter
is called an element. Iron, silver, gold (solids), oxygen (gas) and mercury

(liquid) are di erent elements. ey are made up of only one kind of atoms.

115 di erent elements are found on the earth.
Each element is represented by a symbol. Scientists o en use these symbols

to represent these elements, instead of their names. For example, O is used for
oxygen, N for nitrogen, C for carbon, H for hydrogen and so on.

Compounds

Most substances around us are made up
by combination of more than one kind of Knowledge Zone
elements. e elements of di erent kinds Water is a compound made up of oxygen

and hydrogen where one is needed for

combine in a xed ratio to form a compound. burning, i.e., oxygen and the other burns
For example, oxygen and hydrogen are two itself, i.e., hydrogen and water itself is

elements. ey combine in a xed ratio to used for extinguishing fire.

form a compound, called water. In water,
two atoms of hydrogen combine with one atom of oxygen.

A compound is a totally new substance formed from its elements. Water is totally
di erent in its appearance, physical state and behaviour from that of oxygen and

hydrogen. Water is liquid at room temperature while oxygen and hydrogen are gases.
Elements that form a compound cannot be separated easily. Sugar, salt, etc. are

some examples of compounds.
• Hands-on Learning
Activity

Take a mixture of iron filings and sulphur powder in a china dish and heat it over a burner. What
happens to iron and sulphur? Can you now separate the two elements?

Mixture
When two or more substances are put together and they do not combine, they

form a mixture. It does not lead to the formation of a new substance.

Take some iron nail and tea grains in a china dish. Mix them well. Take a magnet
and roll it over the mixture. What happens?

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