The partial Lewis structure that follows is for a hydrocarbon molecule. In the full Lewis structure, each carbon atom satisfies the octet rule, and there are no unshared electron pairs in the molecule. The carbon—carbon bonds are labeled 1, 2, and 3. (c) Which carbon—carbon bond is the strongest one?

Key Concepts

Octet Rule

The octet rule is a chemical guideline stating that atoms tend to bond in such a way that they each have eight electrons in their valence shell, achieving a stable electron configuration similar to that of noble gases. In hydrocarbons, carbon atoms typically form four bonds to satisfy this rule, influencing the molecule's stability and reactivity.

Types of Carbon-Carbon Bonds

Carbon atoms can form single, double, or triple bonds with each other, with each type having different strengths and characteristics. Single bonds (sigma bonds) are the weakest, while double bonds (one sigma and one pi bond) are stronger, and triple bonds (one sigma and two pi bonds) are the strongest. The bond strength affects the overall stability of the molecule.

Bond Strength and Length

Bond strength is inversely related to bond length; shorter bonds are generally stronger due to the increased overlap of atomic orbitals. In hydrocarbons, the presence of multiple bonds (double or triple) results in shorter bond lengths compared to single bonds, making them stronger. Understanding this relationship is crucial for determining which carbon-carbon bond is the strongest.