Skip to main content
Ch.10 - Chemical Bonding II: Molecular Shapes & Valence Bond Theory
Chapter 10, Problem 36

Determine the electron geometry, molecular geometry, and idealized bond angles for each molecule. In which cases do you expect deviations from the idealized bond angle? a. CF4 b. NF3 c. OF2 d. H2S

Verified step by step guidance
1
Determine the electron geometry for each molecule using VSEPR theory.
Determine the molecular geometry for each molecule based on the electron geometry and the number of lone pairs.
Identify the idealized bond angles for each molecular geometry.
Consider the presence of lone pairs and their effect on bond angles to identify any deviations from the idealized bond angles.
Summarize the electron geometry, molecular geometry, idealized bond angles, and any expected deviations for each molecule.

Verified Solution

Video duration:
2m
This video solution was recommended by our tutors as helpful for the problem above.
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Electron Geometry

Electron geometry refers to the spatial arrangement of all electron groups (bonding and lone pairs) around a central atom. It is determined using the VSEPR (Valence Shell Electron Pair Repulsion) theory, which states that electron groups will arrange themselves to minimize repulsion. Common geometries include linear, trigonal planar, tetrahedral, and octahedral, each associated with specific numbers of electron groups.
Recommended video:
Guided course
03:56
Electron Geometry

Molecular Geometry

Molecular geometry describes the three-dimensional arrangement of atoms in a molecule, considering only the positions of the nuclei of the atoms. While electron geometry includes lone pairs, molecular geometry focuses on the shape formed by the atoms themselves. For example, a molecule may have a tetrahedral electron geometry but a trigonal pyramidal molecular geometry if it has one lone pair.
Recommended video:
Guided course
01:33
Molecular Geometry with Two Electron Groups

Idealized Bond Angles and Deviations

Idealized bond angles are the angles between adjacent bonds in a molecule, predicted by the electron geometry. For instance, in a tetrahedral arrangement, the ideal bond angle is 109.5 degrees. Deviations from these angles can occur due to factors such as lone pair repulsion, differences in electronegativity, or steric hindrance, which can alter the spatial arrangement of atoms and affect bond angles.
Recommended video:
Guided course
01:17
Ideal Bond Angle Example