Difficulty: Easy
Correct Answer: True — neighboring atoms significantly perturb electron states and form bands
Explanation:
Introduction / Context:Band theory explains why metals conduct electricity so well. In a crystal, each atom is surrounded by many neighbors. The overlap of their valence-electron wave functions means electrons can no longer be described as belonging to single atoms. Instead, their allowed energies spread into bands. This question checks your conceptual grasp of how interatomic interactions in a lattice transform discrete atomic levels into continuous energy bands that govern metallic behavior.
Given Data / Assumptions:
Concept / Approach:When many identical atoms come together, their discrete atomic energy levels split due to quantum mechanical overlap and Pauli exclusion. With N atoms, each level splits into N closely spaced levels that merge into bands as N becomes macroscopic. The perturbation from neighboring atoms is therefore strong for valence electrons, producing a conduction band that is partially filled in metals, enabling high electrical and thermal conductivity.
Step-by-Step Solution:
Consider isolated atoms: discrete levels such as 3s, 3p, etc.Bring atoms together in a lattice: electron wave functions overlap and levels split.In a macroscopic crystal: the split levels form nearly continuous bands (valence and conduction).In metals: the Fermi level lies within a band or overlaps bands, allowing free electron motion.Verification / Alternative check:
Free-electron and nearly free-electron models recover metallic dispersion E(k) and explain observed Fermi surfaces and conductivity.Why Other Options Are Wrong:
Isolated atomic states (False option) cannot explain metallic conduction.Temperature does not erase lattice potential; band formation persists.Amorphous vs. crystalline does not negate band formation; periodicity refines, but overlap remains.Core electrons are localized; valence electrons are the ones most perturbed.Common Pitfalls:
Confusing core localization with valence delocalization; thinking temperature alone creates bands.Final Answer:
True — neighboring atoms significantly perturb electron states and form bands
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