Why things conduct electricity
2 marks · EasyExplain why molten potassium iodide conducts electricity, but solid potassium iodide does not.
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Molten potassium iodide conducts electricity because the ions are free to move; in the solid, the ions are held in a lattice and cannot move.
Also accept: In the molten state, ions can move and carry charge, but in the solid state the ions are fixed in place.
Common mistakes: Mentioning electrons instead of ions
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Marking points
M1 · 1 mark · States that ions are free to move in the molten state.
A1 · 1 mark · States that in the solid, ions are fixed/not free to move.
Worked solution
Molten potassium iodide conducts electricity because the ions are free to move and carry charge, but in the solid state, the ions are held in a lattice and cannot move.