Final answer:
Ionic crystals are brittle, unlike metals which are ductile and malleable. This is because ionic crystals have a rigid structure that breaks under force, whereas metals have free electrons that allow atoms to shift without breaking.
Step-by-step explanation:
Compared with metals, ionic crystals are brittle rather than malleable or ductile. Metals, on the other hand, are notable for their ductility and malleability, properties that allow them to be deformed without breaking—metals can be hammered into shapes or drawn into wires. The brittleness of ionic crystals comes from the rigid lattice structure they form; when a force is applied, like-charged ions come too close to each other and repel, causing the crystal to shatter. Unlike malleable and ductile metals, which have free electrons that act as a buffer and allow the layers of atoms to slide past each other, ionic crystals lack this flexibility.