Metals' Thermal Conductivity from Particle Packing and Free Electrons

Steps:

• Solid metals have particles (atoms or ions) arranged in a dense lattice, meaning they are closely packed.
• Metals contain free electrons that move easily through this lattice.
• Heat transfer in metals occurs via these free electrons colliding with lattice particles, vibrating them to spread thermal energy.
• Thus, close packing enables efficient conduction, confirmed by metals' high thermal conductivity values.

Why B is correct:

• Free electrons in closely packed metal lattices transfer kinetic energy rapidly, as per the free electron model of metallic bonding.

Why the others are wrong:

• A: Metals have free electrons essential for conduction; "no" ignores this key feature.
• C: Particles in solids are never far apart; this describes gases, poor conductors.
• D: Far-apart particles with free electrons contradict solid metal structure.

Final answer: B