General Science question from JKAS Prelims, 2021 by JKPSC
Among the following theories which one is discuss about metal-free electrons?
Last updated Jun 24, 2026
Correct Answer:
Option D —
Drude-Lorentz theory
Explanation of the Theories
To understand why Drude-Lorentz theory is the correct choice, it is helpful to look at what each theory focuses on:
Drude-Lorentz Theory (Free Electron Theory): Proposed around 1900, this theory treats a metal as a lattice of positive ions submerged in a "gas" of free electrons. These electrons are not bound to any specific atom and can move freely through the metal, which explains electrical and thermal conductivity.
Werner’s Theory: This is the foundation of coordination chemistry. It explains how metal ions form complexes with ligands by satisfying "primary" (oxidation state) and "secondary" (coordination number) valencies. It does not deal with the "sea" of free electrons found in bulk metals.
Sidgwick’s Theory: An extension of Werner's work, Sidgwick introduced the Effective Atomic Number (EAN) rule. It explains the stability of coordination compounds based on the total number of electrons surrounding the central metal atom, rather than free-moving electrons.
Valence Bond (VB) Theory: This theory explains the bonding in molecules and coordination complexes through the hybridization of atomic orbitals and the sharing of electron pairs. It focuses on localized bonds rather than the delocalized free electron gas characteristic of metallic bonding.
Answer verified by Quintessence Classes faculty — Karan Nagar, Srinagar.
