Concept:The kinetic molecular model views gas particles as widely separated, fast-moving molecules with weak intermolecular forces.
Explanation:In a gas, the molecules possess high kinetic energy and move rapidly in random straight-line motion.
The intermolecular forces between gas molecules are very weak.
Therefore, the molecules are not held in fixed positions and do not form regular clusters.
They are very far apart compared with the size of the molecules themselves.
Because the particles are free to move, a gas expands to fill and occupy every available part of its container.
Option B describes particles in clusters, which is not correct for gases under the kinetic model.
Option C describes a solid, where particles vibrate about fixed positions.
Option D describes a solid arrangement with closely packed, regular particles.
Only option A matches the behaviour of gases.
Answer:A. The molecules are very far apart and occupy all the space made available.