Final answer:
Ionic compounds do not conduct electricity in their solid state because their ions are immobile. They become conductive when melted or dissolved in water as electrolytes because the ions are then free to move, allowing current to flow.
Step-by-step explanation:
An ionic compound is composed of cations and anions in a solid structure, and these ions are not free to move, which makes the solid state of ionic compounds non-conductive of electricity.
Unlike metals, which have delocalized electrons that make them good conductors of electricity at lower temperatures, ionic compounds can only conduct electricity when dissolved in water or in a molten state. This is because the ions are free to move in the liquid or aqueous solution, allowing electricity to pass through.
Electrolytes are substances that, when dissolved in water, dissociate into ions, thereby becoming capable of conducting electricity. Solid ionic compounds, having high melting points, do not conduct electricity, but both their solutions and melted forms do because the ions can move freely.