State the reason why carbon forms a covalent compound and not`C^(4+) and C^(-4)`. Also give reasons why covalent compounds are bad conductors of electricity and have law melting and low boiling points.

Explanation

If carbon accepts 4 electrons to form a negative anion `(C^(4-))` the 6 protons in its nucleus cannot hold on to the ten electrons with the 4 accepted electrons. If it donates 4 electrons to form a positive cation `[C^(4+)]`, it needs a lot of energy to do so. So, carbon neither donates nor gains electrons to form a stable atom, it shares its 4 valence electrons forming covalent compounds.
Sine covalent bonds have only shared pairs of electrons and no free electrons, they are bad conductors of electricity.
The covalent compounds are non-polar and so hence have weak intermolecular attractive forces, thus they have low melting and low boiling points.