Valence shell electron repulsion theory VSEPR

Lewis structures of all but the simplest molecules do not show the shape of the molecule. A collection of rules known as valence-shell electron repulsion theory (VSEPR theory), in which regions of electron density (attached atoms and lone pairs) are supposed to adopt positions that minimize their repulsions, is often a helpful guide to the local shape at an atom, such as the tetrahedral arrangement of single bonds around a carbon atom. This theory should also be familiar from introductory chemistry courses. 

The Lewis structures encountered in Chapter 2 are two-dimensional representations of the links between atoms—their connectivity—and except in the simplest cases do not depict the arrangement of atoms in space. The valence-shell electron-pair repulsion model (VSEPR model) extends Lewis s theory of bonding to account for molecular shapes by adding rules that account for bond angles. The model starts from the idea that because electrons repel one another, the shapes of simple molecules correspond to arrangements in which pairs of bonding electrons lie as far apart as possible. Specifically ... 

Now that we know how to determine hybridization states, we need to know the geometry of each of the three hybridization states. One simple theory explains it all. This theory is called the valence shell electron pair repulsion theory (VSEPR). Stated simply, all orbitals containing electrons in the outermost shell (the valence shell) want to get as far apart from each other as possible. This one simple idea is all you need to predict the geometry around an atom. First, let s apply the theory to the three types of hybridized orbitals. 

The other approach to molecular geometry is the valence shell electron-pair repulsion (VSEPR) theory. This theory holds that... 

Due to the simplicity and the ability to explain the spectroscopic and excited state properties, the MO theory in addition to easy adaptability for modern computers has gained tremendous popularity among chemists. The concept of directed valence, based on the principle of maximum overlap and valence shell electron pair repulsion theory (VSEPR), has successfully explained the molecular geometries and bonding in polyatomic molecules. 

The shape of a molecule has quite a bit to do with its reactivity. This is especially true in biochemical processes, where slight changes in shape in three-dimensional space might make a certain molecule inactive or cause an adverse side effect. One way to predict the shape of molecules is the valence-shell electron-pair repulsion (VSEPR) theory. The... 

VSEPR theory The VSEPR (valence shell electron-pair repulsion) theory says that the electron pairs around a central atom will try to get as far as possible from each other in order to minimize the repulsive forces. This theory is used to predict molecular geometry. 

Introducing Valence-Shell Electron-Pair Repulsion (VSEPR) Theory... 

Vacancy mechanism, 266 Valence bond (VB) theory, 139-153. 391-394.474 Valence shell electron pair repulsion (VSEPR) model. 203-206. 217-218... 

The most useful approach in predicting the stereochemistry of coordination compounds is the Valence Shell Electron Pair Repulsion theory (VSEPR theory), which is based on the idea that the electron pairs around an atom will be arranged so as to minimize the repulsion between them. The qualitative foundations of this field were laid by Sidgwick and Powell1 in 1940 and by Gillespie... 

Valence shell electron pair repulsion theory (VSEPR)... 

The Laplacian of the electron density plays a dominant role throughout the theory.191 In addition, Bader has shown that the topology of the Laplacian recovers the Lewis model of the electron pair, a model that is not evident in the topology of the electron density itself. The Laplacian of the density thus provides a physical valence-shell electron pair repulsion (VSEPR) basis for the model of molecular geometry and for the prediction of the reaction sites and their relative alignment in acid-base reactions. This work is closely tied to earlier studies by Bader of the electron pair density, demonstrating that the spatial localization of electrons is a result of a corresponding localization of the Fermi correlation hole. 

Valence-shell electron pair repulsion (VSEPR) theory gives reasonably accurate predictions of bond angles in a molecule. VSEPR theory uses a simple electrostatic model in which groups of electrons around a central atom repel one another and occupy positions as far apart as possible. The number of electron groups, called the steric... 

Atoms are bound into molecules by shared pairs of electrons. Electrons dislike each other because like charges repel each other. Therefore, whether they are lone pairs of electrons or bonding pairs of electrons, electron pairs try to get as far apart in space as is geometrically possible. There is a fancy name that summarizes these simple ideas the VSEPR theory, which stands for Valence Shell Electron Pair Repulsion Theory. Even though the VSEPR theory is founded on fundamentally simple ideas, it is a tremendously powerful tool for predicting the shapes of molecules. 

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