For each molecule (a)–(f), indicate how many different electron-domain geometries are consistent with the molecular geometry shown. a.

Verified step by step guidance

1. Identify the molecular geometry of the molecule shown in the image. The molecule is water (H2O), which has a bent molecular geometry.
2. Determine the number of electron domains around the central atom (oxygen). In water, there are two bonding pairs (H-O bonds) and two lone pairs on the oxygen atom.
3. Recall that electron-domain geometry considers both bonding pairs and lone pairs. For water, the electron-domain geometry is tetrahedral because there are four electron domains (2 bonding pairs + 2 lone pairs).
4. List the possible electron-domain geometries that can result in a bent molecular geometry. The bent molecular geometry can arise from a tetrahedral electron-domain geometry with two lone pairs.
5. Conclude that there is only one electron-domain geometry (tetrahedral) consistent with the bent molecular geometry of the water molecule.

Key Concepts

Electron-Domain Geometry

Electron-domain geometry refers to the spatial arrangement of all electron domains (bonding and non-bonding electron pairs) around a central atom in a molecule. This geometry is determined by the number of electron domains, which can include single bonds, double bonds, triple bonds, and lone pairs. Understanding this concept is crucial for predicting the overall shape of the molecule.

Molecular Geometry

Molecular geometry describes the three-dimensional arrangement of atoms in a molecule, focusing on the positions of the nuclei rather than the electron pairs. It is influenced by the electron-domain geometry but specifically accounts for the actual atoms present, leading to shapes such as linear, bent, trigonal planar, and tetrahedral. For example, the water molecule (H2O) has a bent molecular geometry due to the two hydrogen atoms and two lone pairs on oxygen.

VSEPR Theory

Valence Shell Electron Pair Repulsion (VSEPR) theory is a model used to predict the geometry of individual molecules based on the repulsion between electron pairs in the valence shell of the central atom. According to VSEPR, electron pairs will arrange themselves as far apart as possible to minimize repulsion, which helps determine the molecular shape. This theory is essential for understanding why molecules like water adopt a bent geometry.