Solid State

Solids are substances having definite volume and definite shape. In terms of kinetic molecular model, in solids there is a regular order in the arrangement of the constituting particles (atoms, molecules or ions) i.e. the particles constituting the solids occupy fixed positions These particles are held together by fairly strong forces.

Characteristics of Solids

Some of the common properties of solids, which distinguish them from other two states of matter, are:

• Solids are rigid and have definite shapes.

• Solids have definite volume irrespective of the size or shape of the container in which they are placed.

• Solids are almost incompressible, having compressibility, which is approximately 10⁶ times more than gases.

• Many solids have a crystalline appearance and have definite pattern of angles and planes.

• Solids diffuse very slowly as compared to liquids and gases. Constituent particles are very closely packed in solids permitting very little space for their movement.

• Solids have a much higher density (mass to volume ratio) than that of gases and liquids.

• Most solids become liquids when heated. Some undergo sublimation on heating. The temperature at which a solid changes into liquid is called the melting point and the process is called as melting. Due to the varying natures of solids their melting temperatures vary considerably.