Why do ionic compounds conduct electricity when melted or dissolved but not as a solid?

Why do ionic compounds conduct electricity when melted or dissolved but not as a solid?

• A. In solids ions are held in a fixed lattice; cannot move; in molten/dissolved state ions are free to move and carry charge.
• B. Ions in solids move readily
• C. Only electrons conduct
• D. Ionic compounds do not conduct in any state

Answer: (A)

Electric conduction needs mobile charged particles to carry the current. In a solid ionic compound, the ions are locked into a rigid crystal lattice by strong electrostatic forces, so they can’t move when an electric field is applied. That stops charge flow, so the solid doesn’t conduct. When the compound is melted, the lattice breaks apart and the ions become free to move; these moving ions carry charge and the liquid conducts. The same happens in solution, where the compound dissociates into ions that disperse and move, providing charge carriers. This is why ionic compounds conduct in the molten or dissolved state but not as solids. (Note: metals conduct mainly by moving electrons, which is a different scenario.)

Electric conduction needs mobile charged particles to carry the current. In a solid ionic compound, the ions are locked into a rigid crystal lattice by strong electrostatic forces, so they can’t move when an electric field is applied. That stops charge flow, so the solid doesn’t conduct. When the compound is melted, the lattice breaks apart and the ions become free to move; these moving ions carry charge and the liquid conducts. The same happens in solution, where the compound dissociates into ions that disperse and move, providing charge carriers. This is why ionic compounds conduct in the molten or dissolved state but not as solids. (Note: metals conduct mainly by moving electrons, which is a different scenario.)