Strong Intermolecular Forces Limit Thermal Expansion

Steps:

• Thermal expansion occurs when heating increases particle kinetic energy, causing separation against attractive forces.
• In solids, intermolecular forces are strongest, restricting particle movement and minimizing expansion.
• Liquids and gases have weaker forces, allowing greater particle separation and more expansion.
• Therefore, strong forces in solids explain their lesser expansion compared to liquids and gases.

Why A is correct:

• Strong forces in solids resist particle separation upon heating, aligning with the principle that thermal expansion coefficient decreases with increasing intermolecular force strength.

Why the others are wrong:

• B: Incorrectly states strong forces cause more expansion, opposite to observed behavior.
• C: Misidentifies solids' forces as weak and reverses expansion effect.
• D: Wrongly claims weak forces cause less expansion, contradicting force-expansion relationship.

Final answer: A