5. why are ionic compounds hard but brittle?

# Brief Explanations: Ionic compounds have strong ionic bonds due to the electrostatic attraction between ions. This gives them hardness. However, when a force is applied, the ions of the same charge are brought close together. The resulting repulsion causes the crystal structure to break, making them brittle. # Answer: Ionic compounds are hard because of strong ionic - bond - based electrostatic attraction between ions. They are brittle because when a force is applied, like - charged ions repel each other and break the crystal structure.