The degree of particle arrangement and motion in solids, liquids, and gases dictates their distinctive properties, including shape, volume, compressibility, and fluidity.
Different states of matter have unique qualities that are determined by the arrangement and motion of their constituent particles. Particles in solids have a defined shape and volume because they are tightly packed and vibrate in predetermined locations.
Because their particles move more freely, liquids can flow and conform to the shape of their container without losing their defined volume. Gases have widely dispersed, quickly moving particles, no defined volume or shape, are highly compressible, and react strongly to changes in pressure and temperature. The macroscopic characteristics of every state of matter are determined by interactions between particles.