Question

Write the main properties of particles which decide whether a given substance will exist as a solid/ a liquid or a gas.

Answer 1

The property of particles that decide the state of the matter of the substance are:

1. Intermolecular force of attraction. This is maximum for solids and minimum for liquids.
2. Inter particle distance.
3. Kinetic energy of the particle.

Stronger the force of attraction between particles, the closer the particles are to each other and this gives the substance a definite shape and volume. The moelcules are tightly held and can only vibrate about their position and hence possess very low kinetic energy.
In gases, the attractive forces are weak, the intermolecular distances are large, the substance does not have a definite shape or volume. The particles move about randomly and possess high kinetic energy.