Book 27, Question 24
Why does a salt crystal shatter, but a metal paper clip bends?
In salt, charged particles alternate in a pattern, with plus next to minus.
If a layer slides over by one step, plus faces plus and the particles push apart, so the crystal splits. In a metal, atoms are surrounded by a flowing sea of electrons that holds them together, so layers can slide without breaking. That is why metals bend and many crystals are brittle.