In which state of matter do atoms collide frequently and move rapidly?

Atoms in a gas move rapidly and collide frequently due to the high kinetic energy they possess. In the gaseous state, the atoms or molecules are widely spaced apart compared to liquids and solids, allowing them to move freely and quickly in all directions. This rapid movement leads to frequent collisions between gas particles, which is a characteristic behavior of the gas phase.

In contrast, in solids, the atoms are closely packed together and vibrate in fixed positions but do not move freely. In liquids, while the particles can slide past one another and are more mobile than in solids, they are still not as energetic or dispersed as in gases. Therefore, the defining feature of the gas state is the high energy and frequent movement of its particles, making it the correct answer.