CBSE Class 12-science Answered

Amorphous

Crystalline

A solid substance with its atoms held apart at equilibrium spacing, but with no long-range periodicity in atom location in its structure is an amorphous solid. Examples of amorphous solids are glass and some types of plastic. In amorphous solids there is short range order value of all properties remain same along any direction and are isotropic in nature.

Amorphous solids melt within a range of temperatures.

In crystalline solids you can see there is long range order.

Arrangement of particles in crystalline solids is different along different directions so the value of properties like refractive index or electrical resistance  vary in different direction  and such solids are Anisotropic.

Crystals will melt at a fixed temperature called melting point.