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The Shapes of Molecules and Ions from the VSEPR Theory

The VSEPR Theory: it is the arrangement of atoms in molecules and ions
This theory is applied in the following way:

? Consider molecules (or ions) in which the central atom is covalently bonded to two or more atoms or groups
? Consider all the valence electron pairs of the central atom-both those that are shared in covalent bonds, called bonding pairs, and those that are unshared, called non-bonding pairs or unshared pairs.
? Because electron pairs repel each other, the electron pair of the valence shell tend to stay far apart as possible. The repulsion between non-bonding pairs is generally greater than that between bonding pairs.
? The geometry of the molecule is arrived at by considering all of the electron pairs, bonding and non-bonding, but the shape of the molecule or ion is described by referring to the positions of the nuclei (or atoms) and not by the position of the electron pairs.

Use the VSEPR theory to predict the geometry of each of the following molecules and ions:
a)BH4- b)BeF2 c) NH+ 4 d) H2S e)BH3 f) CF4

Solution Preview

a) There are four bonding pairs. The geometry is tetrahedral.

b)There are two bonding pairs about the central ...

Solution Summary

This solution reveals the amount of bonding and non-bonding pairs as well as the molecular geometry. The attachment files contains six pictures of the molecules and ions in its molecular shape.