Explain the process of melting in terms of particle energy and arrangement.

Melting occurs when a solid is heated, causing its particles to gain energy. As the energy increases, the particles vibrate more vigorously, eventually overcoming the forces holding them in a fixed position, leading to a change in arrangement from a structured solid to a more disordered liquid state.

Unit lens: Check the units before giving the final statement so the physics quantity is not swapped. This question asks: Explain the process of melting in terms of particle energy and arrangement. The correct response is Melting occurs when a solid is heated, causing its particles to gain energy. As the energy increases, the particles vibrate more vigorously, eventually overcoming the forces holding them in a fixed position, leading to a change in arrangement from a structured solid to a more disordered liquid state., because changes of state are explained by particle energy and arrangement. In Changes of state, the marking point should connect directly to explain melting using increased particle energy and changed particle arrangement. If the question includes values, the working must keep the appropriate unit and operation; if it is an explanation, it must name the relevant particle behaviour or energy change. This item belongs to Changes of state and the particle model, so avoid answers that switch to a different quantity, confuse heat with temperature, or describe gas pressure without collisions when collisions are the reason. Checkpoint 121 is distinct because it uses this exact question context and the unit lens rather than a generic particle-model sentence.