Question

ich of the following summarizes a change that takes place as a solid turns
particles move closer together.
particles become less ordered.
intermolecular forces between particles become stronger.
particles have a decrease in mobility.

Explanation:

When a solid turns to a liquid (melting), the particles gain energy. In a solid, particles are in a highly ordered, fixed - position arrangement. As it melts:

• Particles do not move closer together. In fact, in some cases (like ice - water), the density of the liquid is higher than the solid (for water, ice is less dense than liquid water, but the general concept is that the volume change is not always a simple "closer together" in terms of particle - to - particle distance in a strict sense).
• Intermolecular forces become weaker. In a solid, strong intermolecular forces hold particles in place. As it melts, these forces are partially overcome.
• Particle mobility increases. In a solid, particles vibrate around fixed positions. In a liquid, they can move more freely.
• Particles become less ordered. In a solid, there is a regular, repeating pattern (crystal lattice in many solids). In a liquid, the order is disrupted.

Answer:

Particles become less ordered.