Final answer:
Molecular shapes are determined by the electron-pair geometry around a central atom and the number of lone pairs, which affect the molecular structure. Linear, bent, trigonal planar, trigonal pyramidal, and tetrahedral are shapes corresponding to specific arrangements of bonds and lone pairs around the central atom.
Step-by-step explanation:
The task of matching molecular shapes to the correct Lewis structures involves understanding electron-pair geometries and how the presence of lone pairs affects molecular shape. To determine the shape of a molecule, one should first identify the electron-pair geometry by considering the number of regions of electron density around the central atom, then use the number of lone pairs to determine the molecular structure, selecting arrangements that minimize electron pair repulsion. Here is how the molecular shapes match:
- Linear– This molecular shape corresponds to a central atom with two regions of electron density and no lone pairs, resulting in a straight-line geometric configuration.
- Bent– Also known as angular, this shape generally appears when the central atom has three regions of electron density, two of which are bonded to atoms and one is a lone pair, or when there are four regions with two lone pairs, giving a bent geometry.
- Trigonal Planar– This shape occurs when the central atom is surrounded by three regions of electron density with no lone pairs.
- Trigonal Pyramidal– A molecule with a tetrahedral electron-pair geometry but one lone pair results in a trigonal pyramidal shape.
- Tetrahedral– This shape is seen when there are four regions of electron density around the central atom, all of which are bonded to surrounding atoms and there are no lone pairs.