Valence shell electron-pair VSEPR model

Before discussing the AIM theory, we describe in Chapters 4 and 5 two simple models, the valence shell electron pair (VSEPR) model and the ligand close-packing (LCP) model of molecular geometry. These models are based on a simple qualitative picture of the electron distribution in a molecule, particularly as it influenced by the Pauli principle. 

Wilson and Geratt [56] discussed a pair-function model constructing geminals from non-orthogonal one-electron orbitals. Their calculations, performed on the water molecule, supported qualitative valence-shell electron-pair (VSEPR) models [57] of directed valence. 

VSEPR model Valence Shell Electron Pair Repulsion model, used to predict molecular geometry states that electron pairs around a central atom tend to be as far apart as possible, 180-182... 

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 ... 

Example the n = 2 shell of Period 2 atoms, valence-shell electron-pair repulsion model (VSEPR model) A model for predicting the shapes of molecules, using the fact that electron pairs repel one another. 

Having introduced methane and the tetrahedron, we now begin a systematic coverage of the VSEPR model and molecular shapes. The valence shell electron pair repulsion model assumes that electron-electron repulsion determines the arrangement of valence electrons around each inner atom. This is accomplished by positioning electron pairs as far apart as possible. Figure 9-12 shows the optimal arrangements for two electron pairs (linear),... 

Once computed on a 3D grid from a given ab initio wave function, the ELF function can be partitioned into an intuitive chemical scheme [30], Indeed, core regions, denoted C(X), can be determined for any atom, as well as valence regions associated to lone pairs, denoted V(X), and to chemical bonds (V(X,Y)). These ELF regions, the so-called basins (denoted 2), match closely the domains of Gillespie s VSEPR (Valence Shell Electron Pair Repulsion) model. Details about the ELF function and its applications can be found in a recent review paper [31],... 

The VSEPR (Valence shell electron pair repulsion) Model... 

VSEPR Model valence shell electron pair repulsion model, model used to predict the geometry of molecule based on distribution of shared and unshared electron pairs distributed around central atom of a molecule... 

The distortion produced by the lone pairs is traditionally described using the Valence Shell Electron Pair Repulsion Model (VSEPR model) (Gillespie and Hargittai 1991), which assumes that each pair of electrons in the valence shell is... 

In the valence-shell electron-pair repulsion model, or VSEPR model, we focus attention on the central atom of a molecule, such as the B atom in BF3 or the C atom in C02. We then imagine that all the electrons involved in bonds to the central atom and the electrons of lone pairs belonging to that atom lie on the surface of an invisible sphere that surrounds it (Fig. 3.3). These bonding electrons and lone pairs are regions of high electron concentration, and they repel one another. To minimize their repulsions, these regions move as far apart as possible on the surface of the sphere. Once we have identified the most distant ... 

This chapter reviews molecular geometry and the two main theories of bonding. The model used to determine molecular geometry is the VSEPR (Valence Shell Electron Pair Repulsion) model. There are two theories of bonding the valence bond theory, which is based on VSEPR theory, and molecular orbital theory. A much greater amount of the chapter is based on valence bond theory, which uses hybridized orbitals, since this is the primary model addressed on the AP test. 

Some simple rules were supported by empirial evidence, valence shell electron pair repulsion model (VSEPR) and MO calculations, both semiempirical and ab initio. These rules could explain those features of molecular geometry which have been characterized by structural investigations using spectroscopic and diffraction techniques. 

The geometric structure of the covalent binary halides, whether neutral or complexed ions, can be explained on the basis of the Nyhotm-Gillespie rules known as the Valence Shell Electron Pair Repulsion Model (VSEPR) theory the geometrical arrangements of the bonds around an atom in a species depends on the total number of electron pairs in the valence shell of the central atom, including both bonding... 

Once a Lewis structure is drawn, you can determine the molecular geometry, or shape, of the molecule. The model used to determine the molecular shape is referred to as the Valence Shell Electron Pair Repulsion model, or VSEPR model. This model is based on an arrangement that minimizes the repulsion of shared and unshared pairs of electrons around the central atom. 

The Basic VSEPR (Valence-Shell Electron-Pair Repulsion) Model... 

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