Q. Differentiate crystalline and amorphous materials?
(a)Crystalline solids: Those solids in which the, ions atoms or molecules in a definite regular repeated three dimensional pattern are called solids. Thus the atoms or molecules in crystalline solid are arranged just as the sliders do on the parade ground.
e.g.Calcite, rock-salt, quartz, sugar-mica, diamond etc.
(b)Amorphous solids: Those solids in which the constituent atoms or molecules are not arranged in a definite pattern, repeating in three dimensions are called amorphous solid or materials.
e.g.plastic, glass etc.
(a) The constituent's ions or molecules in a given crystalline solid are arranged in a definite geometrical pattern.
The constituent's atoms or molecules in these solids are not arranged in a regular definite geometrical pattern.
(b) These have a definite external geometrical shape.
These are not regular in their external shape.
(c) These have a long range order of atoms or molecules.
These do not have a long range order of atoms or molecules.
(d) All the bonds among molecules in these solids are equally strong. The crystalline solids have a sharp melting point.
Amorphous solid do not have a sharp melting point, because the weakest bond get reputed at lower temperature and stronger bonds get reputed at higher temperature.
(e) These are anisotropic i.e. the bond of crystalline solids have directional properties.
These solids sre isotropic as their physical properties are same in all direction.
In crystalline solids the angles between the flat surfaces of the crystal are constant.
These are super cooled liquid of high viscosity.