Science (086) — AI-generated practice question

In solid ionic compounds, the ions are held in fixed positions in a rigid crystal lattice and cannot move freely. Since electric current requires the movement of charged particles (ions), ionic solids do not conduct electricity.

When melted or dissolved in water, the ionic lattice breaks down and the ions become free to move. These freely moving ions carry electric charge and thus conduct electricity.

In short: Conductivity requires mobile charged particles. Solid state → ions fixed, no conduction. Molten/dissolved state → ions free to move → conduction occurs.

Source: Chapter 3 (Metals and Non-metals / Ionic compounds), as referenced in Chapter 4, Section 4.1

• Examiners look for two clear points: (1) why solids don't conduct — ions are fixed in lattice, (2) why molten/dissolved state does conduct — ions become free/mobile.
• Use the terms rigid lattice, free ions, and mobile charged particles for full marks.
• This is a 3-mark answer, so cover both states with a brief reason for each, plus a linking idea (conductivity needs mobile ions). Don't write more than 3–4 sentences.