Which statement correctly identifies a characteristic of carbon in organic chemistry?

• A. It forms six covalent bonds
• B. It typically gains electrons to become negative
• C. It is always a metal
• D. It forms four covalent bonds most commonly

Answer: (D)

Carbon’s ability to form four covalent bonds is central to organic chemistry. With four valence electrons, it tends to share electrons with other atoms to complete its octet, usually resulting in four bonds. This tetravalence lets carbon build a vast variety of structures—chains, branches, rings, and both single and multiple bonds—giving rise to the enormous diversity of organic compounds. So, four covalent bonds most commonly is the defining characteristic. The other ideas don’t fit as well: six covalent bonds would require more valence electrons than carbon has; carbon typically shares electrons rather than gaining them to become negatively charged in organic contexts; and carbon is a nonmetal, not a metal.