Which of the following best describes a feature of the Particle Model of Matter?

• A. Particles do not interact
• B. Particles are stationary
• C. There are no spaces between particles
• D. There are spaces between particles and they attract each other

Answer: (D)

Matter is made of tiny particles that are always moving and are spaced apart, not clumped together. In this model, particles can move past each other, there are gaps between them, and they attract each other with forces. That combination—having spaces between particles and attraction—best describes how the Particle Model explains how matter behaves, including why substances can flow or change state when energy is added or removed. The other ideas—particles not interacting, being stationary, or having no spaces—don’t fit because they ignore motion, gaps, or the forces that hold matter together.