Edexcel IGCSE Chemistry 1.43 Ionic conductivity
Practise deciding when ionic substances conduct electricity by tracking whether ions are fixed in a solid or mobile when molten or aqueous.
- Syllabus
- First assessment 2019
- Course
- Chemistry 4CH1
Practise deciding when ionic substances conduct electricity by tracking whether ions are fixed in a solid or mobile when molten or aqueous.
This question is about Group 2 elements and their compounds.
The table lists some substances and shows which substance conducts electricity.

Explain these observations.
Refer to structure and bonding in your answer.
An explanation linking the following five points:
- water is covalent / water is a molecule
- water has not enough charged particles / not enough ions / no delocalised electrons, so it cannot conduct electricity / carry a current
- magnesium chloride is an ionic compound / substance / solid / lattice
- ions in solid magnesium chloride are fixed in position / do not move
- ions in aqueous magnesium chloride solution are free to move
Marking guidance:
- Do not award the aqueous-conduction mark if the answer mentions electrons moving or delocalised electrons.
- Lose 1 mark if there is any mention of intermolecular forces in magnesium chloride.