Final answer:
In larger molecules, it is more appropriate to discuss the geometry surrounding each central atom, rather than the molecule's overall geometry. The VSEPR theory helps in understanding the local geometries that determine the molecule's shape and reactivity. This concept is essential in predicting how a molecule will behave in chemical processes.
Step-by-step explanation:
In larger molecules, it makes more sense to talk about the geometry about a central atom rather than the geometry of the molecule as a whole. Geometries have a significant impact on the shape a particular molecule can assume. For example, methane (CH4) and ethane (C₂H₆) consist of simple molecules with clear central atoms, and their shapes can be easily predicted using the valence shell electron pair repulsion (VSEPR) theory. This theory suggests that electron pairs repel each other to maximize the distance between them, affecting the overall geometry of the molecule.
Larger molecules do not have a single central atom but are connected by a chain of interior atoms that each possess a 'local' geometry. It's the arrangement of these local structures around each central atom that influence the overall molecular structure. Knowing the local geometry helps predict behavior such as chemical reactivity and physical properties. The molecular geometry, which is the arrangement of the bonded atoms in space, is often more complex in larger molecules due to the presence of multiple central atoms.
Understanding these concepts is crucial because a molecule's shape greatly affects its functionality in chemical reactions. Hence, when discussing larger molecules, we tend to focus on the local geometries of interior atoms to gain insight into the molecule's overall structure and reactivity.