Helium (He), Argon (Ar), and Xenon (Xe) are isolated from the atmosphere and placed in the same container. How does the average kinetic energy of these atoms compare?

• A. Ar > Xe > He
• B. They are equal
• C. Xe > Ar > He
• D. Xe < Ar < He
• E. Ar < Xe < He

Answer: (B)