Medium
Most non-metals are poor conductors of electricity. Which of the following non-metallic forms is a good conductor of electricity?
Explanation
Explanation
Step 1: Carbon is a non-metal that exists in different forms (allotropes) such as diamond and graphite.
Step 2: In diamond, each carbon atom is bonded to four others, so no free electrons are available; diamond does not conduct electricity.
Step 3: In graphite, each carbon atom is bonded to three others in layers, leaving one free electron per atom, so graphite conducts electricity (used in electrodes and dry cells).
Step 4: Sulphur and phosphorus are typical non-metals and are poor conductors.
Answer: Graphite.
PRO TIP
Re-check your working by substituting the answer back into the original question.