What happens to the energy of particles in a solid when it melts?

The correct answer is The energy increases and particles move further apart..

Graph lens: Read the trend, flat section, gradient, or axis labels before explaining the physical meaning. This question asks: What happens to the energy of particles in a solid when it melts. The correct response is The energy increases and particles move further apart., 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 123 is distinct because it uses this exact question context and the graph lens rather than a generic particle-model sentence.