Page 210 - New Medley 5 Semester 2

Composition of Matter

Matter is made up of atoms and molecules. Atoms are tiny particles which form

the building blocks of matter. ey are so small that they cannot be seen with

the naked eye. Di erent objects are made up of di erent types of atoms. Most

atoms do not stay alone. ey combine with other atoms of same or di erent

kinds to form molecules. Atoms or molecules make a material, just like bricks
make a wall.

Molecules always keep moving and attract other surrounding molecules. Molecules

in solid, liquid and gaseous states behave di erently.

Features of Matter in Three Different States

Solid Liquid Gas

1. Solids have a de nite shape Liquids have no definite Gases neither have a de nite

and de nite volume. shape but have a de nite shape nor a di nite volume.

volume.
2. Molecules in a solid lie very Molecules in a liquid are Molecules in a gas are far
close to each other. not as close to each other apart.
as in solids.

3. The molecules are very The molecules are not e molecules have very
strongly attracted towards attracted towards each weak forces between them.

each other and their other with strong forces and So they move apart much
movement is very slow. therefore, they move faster faster as compared to solids
as compared to solids. and liquids.

4. Solids cannot ow. Liquids can ow. Gases ow in all directions.
1 • Remembering

Fill in the blanks.
1. Everything is made up of .

2. e exists in three di erent forms.
3. Molecules in are very close to each other.

4. e matter in gaseous state, neither has a xed nor a xed

.

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