CH-1010 Chapter Notes - Chapter 5: Optical Rotation, Chemical Formula, Aurora
Document Summary
The shape of a molecule can affect many properties of the substance, including its physical state at room temperature, its aroma, its biological activity, and its distribution in the environment. Lewis structures show how atoms are connected in molecules, but they don"t show how the atoms are oriented in three dimensions, nor do they necessarily show the overall shape. Vsepr theory applies this principle by assuming that pairs of valence electrons are arranged about central atoms in ways that minimize repulsions between the pairs. To predict molecular shape using vsepr, we must consider two things: Electron-group geometry, which defines the relative positions in three-dimensional space of all the bonding pairs and lone pairs of valence electrons on the central atom. Molecular geometry, which defines the relative positions of the atoms in a molecule. To accurately predict molecular geometry we first need to know electron-group geometry.
