All metals (copper, iron, lead, magnesium etc) and graphite, a non-metal. Most non-metals (sulphur, iodine, charcoal etc.) Most solid compounds (All gases are non-conductors)
Liquids are classified in three groups as regards their conductivity of electricity:
(i) Those that pass an electric current and are not decomposed by if (conductors)
(ii) Those that pass an electric current and are decomposed by it (electrolytes)
(iii) Those that do not pass an electric current (non-electrolytes).
In summary, the following substances are electrolytes:
- Molten salts
- Solutions of salts in water
- Solutions of acids
- Solutions of alkalis
Metallic conductivity:
- Electrons flow(carry charge)
- It is a property of elements, graphite and alloys
- It takes place in solids and liquids
- No chemical change takes place.
Electrolytic conductivity:
- Ions flow (carry charge)
- It is a property of ionic compounds
- Takes place in liquids (molten salts) and solutions but not solids
- Chemical decomposition takes place.