Question

Define : 

(1) Crystalline solid. 

(2) Amorphous solid.

Answer 1

(1) Crystalline solid : A homogeneous solid in which the constituent particles like atoms, ions or molecules are arranged in a definite repeating pattern throughout the solid is called crystalline solid.

For example, 

NaCl, KNO₃, etc.

(2) Amorphous solid : A substance which appears like solid but does not have perfectly ordered crystalline structure and no regular arrangement of constituent particles in structure is called amorphous solid. 

For example,

glass, rubber, plastics, etc.