Atomic bonding in conductors — copper valence electron: What is the relative strength of attraction between a copper atom’s single valence electron and its nucleus?

Introduction / Context:
Electrical conductivity depends on how tightly outer electrons are bound to atoms. Copper is a premier conductor used in wiring and electronics. Understanding why hinges on the binding of its valence electron, which affects electron mobility and resistivity.

Given Data / Assumptions:

• Element: copper (Cu), atomic number 29.
• Electronic configuration (simplified): [Ar] 3d^10 4s^1.
• We consider the effective nuclear attraction on the outermost (valence) electron.

Concept / Approach:
In metals like copper, the single 4s valence electron is relatively loosely bound due to shielding by inner electron shells and the metallic bonding environment. This weak attraction allows electrons to move freely under an electric field, producing high conductivity and low resistivity compared to semiconductors or insulators.

Step-by-Step Solution:
Recognize copper’s valence electron occupies a higher-energy shell (4s) shielded by filled inner shells.Effective nuclear charge on this electron is reduced by shielding, weakening attraction.In a metallic lattice, valence electrons form an electron “sea,” enabling easy drift motion.Therefore, the attraction is best described as weak compared to inner-shell electrons.

Verification / Alternative check:
Empirical data: copper’s low resistivity and high conductivity are consistent with a loosely bound valence electron, corroborating the conceptual explanation.

Why Other Options Are Wrong:
(a) Strong attraction contradicts copper’s excellent conductivity. (b) “Neutral” is not a meaningful descriptor of electrostatic attraction. (d) It is possible to infer; materials science and band theory support the weak-binding model.

Common Pitfalls:
Confusing atomic binding with lattice energy; assuming all outer electrons are tightly bound as in covalent solids (e.g., diamond).

Final Answer:
Weak.