Describe the arrangement, movement and energy of particles in a solid.

• A. Regular arrangement, no movement, low energy.
• B. Random arrangement, random movement, high energy.
• C. Regular arrangement, some movement, high energy.
• D. Random arrangement, some movement, low energy.

Answer: (A)

In a solid, particles are arranged in a regular, fixed pattern and stay near their positions because the forces between them are strong. They don’t flow past each other; instead, they oscillate very slightly around their spots. This limited motion means the particles have low kinetic energy. So the best description is a regular arrangement with movement only as small vibrations and with low energy. The other ideas describe looser packing, more movement, or higher energy, which would correspond to liquids or gases rather than a solid.