Why does carbon form compounds mainly by covalent bonding?
Carbon atoms have 4 valence electrons in their valence shell, it needs to gain or lose 4 electrons to attain the noble gas configuration. (i) It could gain four electrons forming C4- anion. But it would be difficult for the nucleus with six protons to hold on to ten electrons. (ii) It could lose four electrons forming C4+ cation. But it would require a large amount of energy to remove four electrons from its outermost shell. Therefore, carbon shares its valence electrons to complete its octet with other atoms to form covalent bonds
