Question

why do solid have a definite shape whereas gases don't. Explain using the particle model of matter.

Answer 1

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Solids have fixed shape due to strong intermolecular force of attraction between them. The liquids and gases have molecules with less intermolecular force of attraction and hence they can flow and take shape of the container.

Answer 2

Answer:

The particles are very close together and held in place by strong forces (bonds). Their particles cannot move around, but they do vibrate. Because the particles cannot move around, a solid has a fixed shape. ... Gases don't have a fixed shape or a fixed volume.