Consider the molecule $C_2{H}_4$ (ethene), where one of the carbon atoms is highlighted. In how many sigma bonds does the highlighted carbon atom participate?

• A. $1$
• B. $2$
• C. $4$
• D. $3$

Answer: (C)

Verified step by step guidance

1. Identify the structure of ethene (C\_2H\_4). Ethene consists of two carbon atoms connected by a double bond, and each carbon is 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. The sigma bond is the first bond formed and lies along the axis connecting the two nuclei.
3. Focus on the highlighted carbon atom. Count all the sigma bonds it forms: one sigma bond with the other carbon atom and one sigma bond with each hydrogen atom attached to it.
4. Sum the sigma bonds: the highlighted carbon has one sigma bond to the other carbon and two sigma bonds to two hydrogens, totaling three sigma bonds so far.
5. Remember that each carbon atom in ethene is sp\^2 hybridized, which means it forms three sigma bonds in total (two with hydrogens and one with the other carbon) and one pi bond (part of the double bond). Therefore, the highlighted carbon participates in 3 sigma bonds.