Wave particle duality is the concept in quantum mechanics that every particle or quantum entity may be described as either a particle or a wave. It expresses the inability of the classical concepts "particle" or "wave" to fully describe the behaviour of quantum-scale objects.
Answer:
There is a lot of empty space between them.
Explanation:
The kinetic molecular theory postulates that a substance is made up of tiny particles called molecules. The molecules of a gas are in constant random motion and collide elastically with each other. They also collide with the walls of the container.
The magnitude of intermolecular forces of attraction between gas molecules is very small. Hence gas molecules are largely apart with a lot of empty space between gas molecules.