Crystal lattices Original Scenario-Based Download PDF

Questions

1. 1.

   While exploring a subterranean cavern on a remote moon, an expedition geologist discovers translucent cubic crystals composed of alternating elemental cations and anions arranged in a continuous, three-dimensional lattice. When struck precisely with a diamond-tipped hammer, the specimen does not dent or bend like a metal; instead, it fractures cleanly along flat, smooth planes into smaller geometric fragments. Which microscopic change in the crystal lattice explains this characteristic brittle cleavage under an applied shear force?

   • A) Delocalized valence electrons are expelled from between the atomic cores, causing immediate covalent bond collapse across the impact plane.
   • B) Neutral discrete molecules within the lattice are compressed beyond their equilibrium distances, triggering dominant London dispersion repulsions.
   • C) A slight lateral displacement shifts adjacent layers so that ions of like charge align, creating massive electrostatic repulsion that splits the crystal.
   • D) Thermal shock instantaneously melts the ionic bonds along the fault line, allowing the lattice to liquefy and separate into smooth faces.