Brass is an alloy composed primarily of copper with about 30 % zinc atoms randomly…
CHEMISTRY · Single correct · A Level · Chemistry · Bonding · Bonding
Problem
Brass is an alloy composed primarily of copper with about 30 % zinc atoms randomly dispersed in the lattice. Which statement best accounts for brass having a lower electrical conductivity than pure copper?
(a) The lighter zinc atoms vibrate more rapidly than copper atoms, and the resulting lattice vibrations interfere with electron flow, lowering conductivity.
(b) Zinc atoms donate extra valence electrons that become trapped in localized orbitals, so fewer electrons are available to conduct electricity.
(c) Differences in atomic size between zinc and copper scatter the delocalized electrons, shortening their mean free path and reducing conductivity.
(d) Zinc atoms alter the lattice geometry and create a small band gap, making the alloy behave more like a semiconductor and thus less conductive.