Why things conduct electricity
2 marks · HardExplain why pure, solid silver chloride does not conduct electricity, but when dissolved in water, it does.
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Also accept: Solid silver chloride does not conduct because the ions are held in a lattice and cannot move. When dissolved, the lattice breaks and ions are free to move and carry charge.
Common mistakes: Stating electrons carry charge in silver chloride; Claiming solid ionic compounds conduct
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Marking points
M1 · 1 mark · Recognises that solid silver chloride does not conduct because ions are fixed in place.
M2 · 1 mark · Explains that, when dissolved in water, silver chloride conducts because ions are free to move.
Worked solution
Solid silver chloride does not conduct electricity because its ions are held in a lattice and cannot move. When dissolved in water, the lattice breaks apart; ions become free to move and can carry charge through the solution.