Chemistry Solids NUMS 2023
PMDC Verified Question 30 of 54
Thermal conductivity of metals is due to:
A
Layered structure of metals
B
Freely moving electrons
C
Loosely hold metal atoms
D
Vibrational movement of metals
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: Freely moving electrons
Concept:
Metals are excellent conductors of both heat and electricity due to their unique atomic structure, specifically the "electron sea" model.

Solution:
  • In a metallic lattice, the valence electrons detach from individual atoms and become delocalized, forming a "sea" of freely moving electrons.
  • When heat is applied to one end of a metal, these highly mobile free electrons gain kinetic energy.
  • Because they can move freely and rapidly throughout the entire crystal lattice, they quickly transfer this thermal energy to cooler regions via collisions.
  • Therefore, the high thermal conductivity of metals is primarily due to freely moving electrons.


Why other options are incorrect:
  • D: While vibrational movement of atoms (phonons) does contribute slightly to thermal conductivity, the overwhelmingly dominant mechanism in metals is electron transport.
  • A, C: Metals do not generally have "layered structures" (unlike graphite), and their atoms are tightly packed, not "loosely held".

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

Previous Question All Solids MCQs Next Question

Want to solve full-length papers under timed exam conditions?

Practice with zero-scroll lockdown sprints, dynamic latency zone timers, live peer selection telemetry, and the automated Amber mistake recovery loop.

Enter Arena Sprint iOS App Android App