How many sigma and pi bonds are present in the molecule C2H4 (ethene)?

• A. 5 sigma bonds and 1 pi bond
• B. 6 sigma bonds and 0 pi bonds
• C. 4 sigma bonds and 2 pi bonds
• D. 3 sigma bonds and 2 pi bonds

Answer: (A)

Verified step by step guidance

1. Identify the molecular structure of C2H4 (ethene). It consists of two carbon atoms double bonded to each other, and each carbon atom is bonded to two hydrogen atoms.
2. Recall that a single bond consists of one sigma (\sigma) bond, and a double bond consists of one sigma (\sigma) bond and one pi (\pi) bond.
3. Count the sigma bonds: Each C-H single bond is a sigma bond, so with 4 C-H bonds, there are 4 sigma bonds. The C=C double bond contains one sigma bond, adding 1 more sigma bond, for a total of 5 sigma bonds.
4. Count the pi bonds: The C=C double bond also contains one pi bond, so there is 1 pi bond in the molecule.
5. Summarize the total bonds: C2H4 has 5 sigma bonds and 1 pi bond.