Question

What are the physical properties of ionic crystals.

Answer 1

Ionic crystals are hard, have high melting points, and are brittle. When they melt, the resulting liquids conduct electricity well. These properties reflect the strong attractive forces between ions of opposite charge as well as the repulsion that occur when ions of like charge are placed near each other.
They are brittle and tend to shatter into smaller crystals when stressed. When a crystal is hammered or stressed, ions with like charges are forced into close proximity. The crystal then literally self destructs because of electrostatic repulsion.