Final answer:
AB2 molecules can have linear, bent, or trigonal planar shapes with examples being CO2, H2O, and BeH2, respectively. AB3 molecules can be trigonal planar, trigonal pyramidal, or T-shaped, with examples such as BF3, NH3, and ClO3-.
Step-by-step explanation:
Molecules with the formula AB2 can adopt one of three possible shapes depending on the arrangement of electron pairs around the central atom: linear, bent, or trigonal planar. For example, carbon dioxide (CO2) is linear, water (H2O) has a bent shape, and beryllium hydride (BeH2) is an example of a trigonal planar molecule.
Similarly, molecules with the formula AB3 may exhibit different shapes: trigonal planar, trigonal pyramidal, or T-shaped. Boron trifluoride (BF3) is trigonal planar, ammonia (NH3) is trigonal pyramidal, and chlorate ion (ClO3-) can be described with a T-shaped structure.