Final answer:
Common molecular shapes, determined by VSEPR theory, include linear, bent, trigonal planar, trigonal pyramidal, and T-shaped, influenced by the arrangement of electron pairs around the central atom.
Step-by-step explanation:
The common geometric shapes found in molecules can be largely predicted using the Valence Shell Electron Pair Repulsion (VSEPR) theory. This theory states that electron pairs around a central atom will arrange themselves as far apart as possible to minimize repulsion. The basic geometries are influenced by the number of electron groups around the central atom.
The most common molecular shapes are:
- Linear
- Bent
- Trigonal planar
- Trigonal pyramidal
- T-shaped
For example, methane (CH4) has a tetrahedral shape due to its four bonding electron groups arranging themselves symmetrically around the carbon atom. Ethane (C2H6), on the other hand, has a different arrangement due to its additional carbon atom and hydrogen atoms.