Question

On the basis of molecular theory, explain why solids have a definite shape and a definite volume.

Answer 1

Molecular theory

• The intermolecular spaces are very small and intermolecular forces are very large: Thus, particles in a solid have fixed positions inside a constant volume.
• The molecules in a solid can vibrate about their mean positions, but cannot change their positions: Strong interactions between particles in a solid prevent them from moving around and retaining them in place.
• It is on account of this molecular arrangement, that solids have a definite shape and definite volume: Because particles in a solid vibrate about fixed positions, solids have a defined volume and form.
• They are incompressible.

Thus, solids have a definite shape and a definite volume.