How many covalent bonds can carbon form?

How many covalent bonds can carbon form?

• A. Three.
• B. Two.
• C. Five.
• D. Four.

Answer: (B)

The main idea is valence and octet completion. Carbon has four valence electrons and needs four more to reach a full octet, so it forms covalent bonds by sharing electrons with other atoms. Each bond represents one pair of electrons shared, and the total number of shared electron pairs around carbon sums to four. That means carbon can form four single bonds (as in methane), or, in other ways, a combination that totals four bonds in count—such as two bonds to oxygen via a double bond (two bonds) plus two single bonds to hydrogens, or a triple bond to another carbon plus a single bond to a substituent. In all cases, the total bond count around carbon is four, which is why the correct answer is four, not two.

The main idea is valence and octet completion. Carbon has four valence electrons and needs four more to reach a full octet, so it forms covalent bonds by sharing electrons with other atoms. Each bond represents one pair of electrons shared, and the total number of shared electron pairs around carbon sums to four. That means carbon can form four single bonds (as in methane), or, in other ways, a combination that totals four bonds in count—such as two bonds to oxygen via a double bond (two bonds) plus two single bonds to hydrogens, or a triple bond to another carbon plus a single bond to a substituent. In all cases, the total bond count around carbon is four, which is why the correct answer is four, not two.