Brass is an alloy composed primarily of copper with atoms of zinc of comparable size…
CHEMISTRY · Single correct · A Level · Chemistry · Bonding · Bonding
Problem
Brass is an alloy composed primarily of copper with atoms of zinc of comparable size randomly substituting for some copper atoms in the lattice. Which of the following best accounts for the fact that brass has a lower electrical conductivity than pure copper?
(a) Zinc has fewer valence electrons than copper, so the alloy contains fewer conduction electrons, lowering electrical conductivity.
(b) Substituted zinc atoms disrupt the regular lattice, scattering mobile electrons and decreasing their mean free path.
(c) The presence of zinc increases the number of delocalized electrons, leading to greater electron–electron repulsion and thus lower conductivity.
(d) Because zinc atoms are slightly smaller than copper atoms, the lattice packs more tightly, leaving less space for electrons to move and reducing conductivity.