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. (a) How many hydrogen atoms are in the molecule?

Key Concepts

Lewis Structures

Lewis structures are diagrams that represent the bonding between atoms in a molecule and the lone pairs of electrons that may exist. They help visualize how atoms are connected and how many electrons are shared or unshared. In hydrocarbons, carbon atoms typically form four bonds, and hydrogen atoms form one bond, which is crucial for determining the molecular formula.

Octet Rule

The octet rule is a chemical rule of thumb that states 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. For carbon, this means it can form four bonds, while hydrogen, with only one valence electron, can form one bond to achieve a stable configuration.

Hydrocarbons

Hydrocarbons are organic compounds consisting entirely of hydrogen and carbon. They can be classified as aliphatic (straight or branched chains) or aromatic (ring structures). The number of hydrogen atoms in a hydrocarbon can be determined based on the number of carbon atoms and the types of bonds (single, double, or triple) present, following specific formulas for saturated and unsaturated hydrocarbons.