Question

Diamond is hard and a bad conductor of electricity, while graphite is soft and a good conductor of electricity. Explain.

Answer 1

Diamond is hard and a bad conductor of electricity, while graphite is soft and a good conductor of electricity because:

1. In diamond, each carbon atom is sp³ hybridised and covalently bonded to four other carbon atoms in a 3D tetrahedral network, making it very hard. All valence electrons are involved in bonding, so there are no free electrons, making it a bad conductor of electricity.
2. In graphite, each carbon atom is sp² hybridised and bonded to three other carbon atoms in hexagonal layers. The fourth electron is free (delocalised) and can move, making graphite a good conductor. The layers are held by weak van der Waals forces, so they slide easily, making graphite soft.