Final Answer:
Geometric isomer - (3S,4S)-3,4-dimethylheptane exhibits stereochemistry using wedges and dashes, indicating a specific spatial arrangement around the double bond, thus the correct option is A.
Step-by-step explanation:
(3S,4S)-3,4-dimethylheptane is a stereoisomer that exhibits geometric isomerism. Geometric isomerism occurs due to restricted rotation around a double bond or a ring, leading to different spatial arrangements of substituents. In this compound, the (3S,4S) configuration signifies the stereochemistry at the third and fourth carbon atoms, indicating that the methyl groups at these positions are oriented on the same side in space. To represent this in a structural formula, wedges and dashes are used to depict the three-dimensional arrangement of atoms or groups around the double bond. For (3S,4S)-3,4-dimethylheptane, both methyl groups on the third and fourth carbons would be shown on the same side of the double bond with wedges, signifying their spatial proximity.
Geometric isomers possess different spatial arrangements, impacting their physical and chemical properties. The designation of (3S,4S) implies a specific arrangement of substituents in a chiral molecule, highlighting the configuration around the third and fourth carbon atoms in this case. To distinguish between geometric isomers, it's essential to represent the spatial arrangement accurately, often done using wedge-and-dash line drawings or three-dimensional models to show the orientation of substituents around the double bond. In this scenario, the presence of the (3S,4S) configuration indicates a specific geometric isomer with a defined spatial arrangement of substituents at the specified carbon atoms.
Hence, the use of wedges and dashes to illustrate the spatial arrangement of substituents around the double bond in (3S,4S)-3,4-dimethylheptane signifies its categorization as a geometric isomer. This differentiation in spatial arrangement, highlighted by the use of stereochemical descriptors, demonstrates its distinct configuration and classification within the realm of stereoisomers (option A).