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Ch.9 - Molecular Geometry and Bonding Theories
All textbooksBrown 14th EditionCh.9 - Molecular Geometry and Bonding TheoriesProblem 32
Chapter 9, Problem 32

In which of the following AFn molecules or ions is there more than one F-A-F bond angle: PF6⁻, SbF5, SF4?

Verified step by step guidance
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Step 1: Identify the molecular geometry of each molecule or ion using VSEPR theory. This will help determine the bond angles present in each structure.
Step 2: For PF_6^-, note that phosphorus (P) is the central atom. It has 5 valence electrons, and with 6 fluorine (F) atoms, it forms an octahedral geometry, where all F-P-F bond angles are 90°.
Step 3: For SbF_5, antimony (Sb) is the central atom. It has 5 valence electrons, and with 5 fluorine atoms, it forms a trigonal bipyramidal geometry, which includes two different F-Sb-F bond angles: 90° and 120°.
Step 4: For SF_4, sulfur (S) is the central atom. It has 6 valence electrons, and with 4 fluorine atoms, it forms a seesaw geometry, which also includes two different F-S-F bond angles: less than 90° and less than 120°.
Step 5: Compare the geometries and bond angles of PF_6^-, SbF_5, and SF_4 to determine which have more than one F-A-F bond angle.

Key Concepts

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

Molecular Geometry

Molecular geometry refers to the three-dimensional arrangement of atoms within a molecule. It is determined by the number of bonding pairs and lone pairs of electrons around the central atom, which influences bond angles. Understanding molecular geometry is crucial for predicting the shape of molecules and the angles between bonds, which is essential for answering the question about F-A-F bond angles.
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VSEPR Theory

Valence Shell Electron Pair Repulsion (VSEPR) theory is a model used to predict the geometry of molecules based on the repulsion between electron pairs. According to VSEPR, electron pairs will arrange themselves to minimize repulsion, leading to specific molecular shapes and bond angles. This theory helps in determining whether a molecule has more than one bond angle by analyzing the arrangement of its electron pairs.
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Hybridization

Hybridization is the concept of mixing atomic orbitals to form new hybrid orbitals that can accommodate bonding. The type of hybridization (e.g., sp, sp², sp³) affects the geometry and bond angles of a molecule. Understanding hybridization is important for analyzing the bonding in molecules like PF₆⁻, SbF₅, and SF₄, as it influences the presence of multiple bond angles in their structures.
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Related Practice
Textbook Question

Give the approximate values for the indicated bond angles in the following molecules: (a)

Textbook Question

Give the approximate values for the indicated bond angles in the following molecules: (d)

Textbook Question

Ammonia, NH3, reacts with incredibly strong bases to produce the amide ion, NH2-. Ammonia can also react with acids to produce the ammonium ion, NH4+. (a) Which species (amide ion, ammonia, or ammonium ion) has the largest H¬N¬H bond angle? (b) Which species has the smallest H¬N¬H bond angle?

Textbook Question

(a) Explain why BrF4- is square planar, whereas BF4- is tetrahedral.

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Textbook Question

(b) How would you expect the H¬X¬H bond angle to vary in the series H2O, H2S, H2Se? Explain. (Hint: The size of an electron pair domain depends in part on the electronegativity of the central atom.)