States of Matter
All matter consists of atoms and molecules. Each of these atoms and molecules has certain amount of energy. The level of this energy decides the state in which the matter exists. When heat energy is supplied to matter, this energy level rises. As a result of this, state or the form in which a matter exists can change.
Matter is classified into different categories depending upon its physical or chemical nature.
Physically, matter can exist in three states or forms. These states are: Solid, Liquid and Gas. Atoms or molecules in the solid state have the least energy whereas those in the gaseous state have the maximum energy. In the case of liquids, the atoms or molecules have a midway energy. The basic differences between the three states of matter explained on the basis of dynamic particle model are as follows:
Solid State
In solids, atoms or molecules are closely packed and the intermolecular space or void is minimum. The average distance between particles is of the order 10-8cm; consequently, solids are almost incompressible. In addition, the intermolecular attraction in solids is quite high and for that reason the movement of atoms or molecules in solids is restricted. As a result, atoms or molecules in solids have no freedom of mobility; they only vibrate in their fixed positions.Consequently, a solid will have a definite volume and shape. A solid can form a firm and rigid structure, which allows it to be cut into many shape and sizes. This can result in a solid having any number of free surfaces. A Solid will also have high density, incompressibility and a high melting and boiling point. A solid may be converted to a liquid when it is given heat energy.
A solid- has a definite characteristic shape
- tends to resist deformation of its shape
- is relatively non-compressibleExample: Diamond
Solids can be classified as:
- Crystalline
- Amorphous
