1. Solid particles are packed tightly together in a more rigid formation, therefore giving solids there "solid structure. liquid particles are packed more loosely than solids hence giving them a less rigid structure and in a gas they are pretty much free to move everywhere.
2. For the solid particles because they are tightly packed they are unable to move about very much hence have low kinetic energy.
Liquid phase, the particles of a substance have more kinetic energy than those in a solid. The liquid particles are not held in a regular arrangement, but are still very close to each other so liquids have a definite volume. Particles of a liquid have just enough room to flow around each other, so liquids have an indefinite shape.
Gas particles have a great deal of space between them and have high kinetic energy. If unconfined, the particles of a gas will spread out indefinitely; if confined, the gas will expand to fill its container.