Question

Diamond is a bad conductor of electricity whereas graphite is a good conductor. why

Answer 1

Both are carbon variants. The difference in conductivity is due to the molecular structure of both solids. Recall that carbon has an atomic number of 6, thus 2 electrons are in the first electron layer, and 4 atoms in the outer layer; to form a stable electronic bonding, each carbon atom should get 4 electrons from neighbor atoms.

Diamond: each carbon atom has a covalent bond with four other carbon atoms in a tetrahedral arrangement to form a rigid structure. This is a stable arrangement where the outer electron layer of all atoms are filled with 8 electrons; so, there are no free electrons to move and create electric current. Thus diamond is an insulator/dielectric.

Graphite: covalent structure, with each carbon bonded to three other carbon atoms in a hexagonal arrangement. Three out of four valence electrons are used for covalent bonding with other carbon atoms. Remaining valence electron can easily (with low energy) be moved across the planes of carbon atoms, making it easy to pass an electric current. Thus, graphite is a good conductor.

hope it helps u.........