Question

1. Why is graphite a good conductor of heat and electricity?
2. Why is diamond very
hard?​

Answer 1

1)  one valence electron of each carbon atom remains free, Thus making graphite a good conductor of electricity.

2) In diamond, these electrons are shared with four other carbon atoms to form very strong chemical bonds resulting in an extremely rigid tetrahedral crystal. It is this simple, tightly-bonded arrangement that makes diamond one of the hardest substances on Earth.

Hope it helps you ..