Final answer:
A molecule with formula AB₃ could be trigonal planar with sp² hybridization, trigonal pyramidal with sp³ hybridization, T-shaped with sp³ hybridization, or linear with sp hybridization, depending on the number of lone pairs on the central atom A.
Step-by-step explanation:
A molecule with the formula AB₃ can have one of four different shapes depending on the number of lone pairs on the central atom A. These shapes, along with the hybridization of the central atom, are described below:
- Trigonal Planar: If there are no lone pairs on A, the molecule has a trigonal planar shape. The hybridization of A is sp². An example of this is BF₃.
- Trigonal Pyramidal: With one lone pair on A, the shape is trigonal pyramidal. The hybridization is sp³. NH₃ is a typical example.
- T-shaped: If A has two lone pairs, the shape is T-shaped, and the hybridization remains sp³. ClF₃ is an example of this geometry.
- Linear: With three lone pairs, the shape is linear, and the hybridization of A is sp. This shape is less common for AB₃ molecules but can occur under certain conditions.
The shapes and hybridizations are determined by the VSEPR theory, which states that electron groups around the central atom will arrange themselves to be as far apart as possible.