Why does carbon generally form covalent compounds rather than ionic compounds?

Correct answer: Losing or gaining four electrons is energetically highly unfavourable.

Carbon has four valence electrons in its outermost shell. To complete its octet by ionic bonding, it would have to lose four electrons or gain four electrons. Losing four electrons requires very high energy, while gaining four electrons would create a large negative charge on a small carbon atom. Electron transfer is therefore unfavourable, so carbon usually shares electrons to form covalent bonds. Option B is incorrect because carbon has four valence electrons.