CHEMISTRY · Single correct · A Level · Chemistry · Bonding · Bonding
Problem
When a crystal of NaCl is struck with a hammer, it cleaves cleanly rather than bending. Which statement most accurately accounts for this brittleness?
(a) Because Na^+ ions are much smaller than Cl^- ions, the lattice slips too easily when stressed, causing it to fracture.
(b) When a layer of the crystal is shifted, like-charged ions are brought adjacent to one another, and their strong electrostatic repulsion causes the crystal to cleave.
(c) Ionic solids cannot conduct electricity, so they are unable to redistribute charge under stress, making them brittle.
(d) The face-centered cubic packing of chloride ions creates natural planes of weakness that split whenever force is applied.