Final answer:
All the molecules—Methane (CH₄), Ethene (C₂H₄), Ethyne (C₂H₂), and Propane (C₃H₈)—show an appropriate number of bonds around each carbon atom, adhering to the tetravalency rule in organic chemistry.
Step-by-step explanation:
The molecules that show an appropriate number of bonds around each carbon atom are Methane (CH₄), Ethene (C₂H₄), Ethyne (C₂H₂), and Propane (C₃H₈). Carbon atoms form four bonds each. Methane (CH₄) has one carbon atom with four single bonds to hydrogen atoms, creating a tetrahedral molecule. Ethene (C₂H₄) has two carbon atoms connected by a double bond, with each carbon also bonded to two hydrogens. Ethyne (C₂H₂) consists of a triple bond between two carbon atoms, with each carbon bonded to a single hydrogen. Lastly, Propane (C₃H₈) has a chain of three carbon atoms connected by single bonds, with the terminal carbons bonded to three hydrogens and the central carbon to two hydrogens.
The question whether these molecules show an appropriate number of bonds around each carbon atom can be answered by analyzing their structures. In organic chemistry, a key principle is that each carbon atom forms four covalent bonds. This principle is evident in methane, ethene, ethyne, and propane, which all adhere to the tetravalency rule.