Final answer:
The VSEPR model can be used to predict bond angles of larger molecules. Carbon dioxide (CO₂) has a linear electron pair geometry with bond angles of 180° due to its double bonds. Boron trichloride (BCl₃) has a trigonal planar electron pair geometry with bond angles of approximately 120° due to its three bonding pairs.
Step-by-step explanation:
When predicting bond angles of larger molecules, we can use the VSEPR (Valence Shell Electron Pair Repulsion) model. This model states that electron pairs around a central atom repel each other and try to be as far apart as possible to minimize repulsions. The bond angles in larger molecules can be predicted by determining the electron pair geometry and molecular structure of the molecule.
For example, let's consider carbon dioxide (CO₂), which has a linear electron pair geometry. The bond angles in CO₂ are 180° because it consists of two double bonds between the central carbon and the oxygen atoms. The linear geometry and bond angles in CO₂ can be represented as: O=C=O.
Another example is boron trichloride (BCl₃), which has a trigonal planar electron pair geometry. In BCl₃, the bond angles are approximately 120° because there are three bonding pairs and no lone pairs around the central boron atom. The trigonal planar geometry and bond angles in BCl₃ can be represented as a triangle with the boron atom in the middle and bond angles of 120°: B∆⟨trigonal planar⟩Cl-Cl-Cl.