Electrical conductivity explained

Explain conduction using the correct charged particles and their mobility.

Charge must be able to move

In solid sodium chloride, charged ions occupy fixed positions in a lattice. When melted or dissolved, the ions can move. The presence of ions alone is therefore not enough.

Metals are different

Mobile electrons carry charge in copper. In a sugar solution the dissolved particles are neutral molecules. In this classroom model its conduction is negligible compared with a salt solution.

Worked example

Why does molten NaCl conduct whereas solid NaCl does not?

Both contain Na⁺ and Cl⁻ ions.
In the solid they occupy fixed lattice positions; in the melt they can move.

In the melt, ions transport electric charge.