In general, the kinetic energy of particles depends on their temperature, rather than their phase (solid, liquid, or gas) alone. Kinetic energy is associated with the random motion of particles, which increases with temperature.
In a system at a given temperature, the particles with the least kinetic energy would be those that are moving the slowest on average. At the same temperature, solid particles tend to have the least kinetic energy compared to liquid or gas particles. This is because solids have a more ordered structure with particles closely packed together, and their motion is constrained by intermolecular forces, resulting in lower average velocities.
In liquids, the particles have higher kinetic energy compared to solids because they are less constrained and have more freedom of movement. Liquid particles can move more freely while still being influenced by intermolecular forces.
Gas particles, on the other hand, have the highest kinetic energy among the three phases. In a gas, particles are in constant, rapid motion, colliding with each other and the walls of their container. Gas particles have the greatest degree of freedom to move, as the intermolecular forces are typically weaker compared to solids and liquids.
It's important to note that this description is a generalization and applies to a system at equilibrium. The actual kinetic energy of particles can vary within each phase depending on factors such as temperature, pressure, and specific interactions between particles.