In the molecule ethene ($C_2{H}_4$), how many sigma ($\sigma$) and pi ($\pi$) bonds are present?

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

Answer: (B)

Verified step by step guidance

1. Identify the structure of ethene (C\_2H\_4): it consists of two carbon atoms double bonded to each other, with each carbon atom also bonded to two hydrogen atoms.
2. Recall that a double bond between two carbon atoms consists of one sigma (\sigma) bond and one pi (\pi) bond.
3. Count the sigma bonds: each carbon forms two sigma bonds with hydrogen atoms (2 per carbon, total 4), plus one sigma bond between the two carbons, giving a total of 5 sigma bonds.
4. Count the pi bonds: the double bond between the two carbons includes one pi bond, so there is 1 pi bond in ethene.
5. Summarize the bonding: ethene has 5 sigma bonds and 1 pi bond.