Explain crystalline and amorphous solids.

(N/A) Based on the arrangement of particles,solids are broadly classified as:
$(i)$ Crystalline solids
$(ii)$ Amorphous solids
$(i)$ Crystalline Solids: $A$ solid in which the constituent particles have definite ordered arrangements are called crystalline solids.
$A$ crystalline solid consists of a large number of small crystals,each of them having a definite characteristic geometrical shape.
In a crystal,the arrangement of constituent particles (atoms,molecules or ions) is ordered and repetitive in three dimensions. It has a long-range order which means that there is a regular pattern of arrangement of particles which repeats itself periodically over the entire crystal.
Crystalline solids have a sharp melting point and at a characteristic temperature,they melt abruptly and become liquid. They are anisotropic,meaning their physical properties like electrical resistance or refractive index show different values when measured along different directions. Examples include $NaCl$ and quartz.
$(ii)$ Amorphous Solids: The term amorphous comes from the Greek word 'amorphos',meaning 'no form'.
In amorphous solids,the constituent particles (atoms,molecules or ions) do not have a long-range order. They have only short-range order,where the regular and periodically repeating pattern is observed only over short distances.
Amorphous solids soften over a range of temperature and can be moulded and blown into various shapes. They are isotropic in nature,meaning their physical properties are the same in all directions. Examples include glass,rubber,and plastics.