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Unformatted text preview: lar Geometry
Molecular Geometry--the shape of the molecule without the Geometry-- lone pairs of electrons. To determine the molecular geometry of a molecule: Build a model by: Determining the Lewis structure of the molecule. 1. Determine the Electronic Geometry by regions of high 2. electron density around the central atom. Remove the lone pairs of electrons and note the shape of 3. the molecule. 47 Molecular Geometry
This is the actual shape of the molecule. Lone pairs of electrons are very repulsive, more than 1. bonded electrons, and have a very large effect on the actual shape of the molecule. If there are lone pairs of electrons around the central 2. atom, the bonds around the central atom will be repulsed and will move away from the region of lone pairs. The geometry around the central atom is not the same 3. with lone pairs of electrons. The bond angles are not geometrical and shape will be 4. different than the geometrical structure that is predicted by the regions of high electron density. 48 Molecular Geometry
The electronic geometry and molecular geometry of a molecule are the same if there are no lone pairs of electrons on the central atom. atom. The bond angles will be the same for electronic and molecular geometries. geometries. 49 Polarity
Polarity of a molecule is determined by the symmetry of the electron density around the central atom.
(The Electronegativity difference between atoms around the central atom in bonds must be equal and opposite in magnitude) 50 Polarity
Polarity of a molecule is based on the symmetry of the geometric structure. The bond angles in the water 3-D structure are less 3than 109.5o, therefore; the molecule is no longer symmetrical. If the molecule is not symmetrical, then the molecule is polar. Water happens to be very polar. 51 Polarity
When a molecule is com...
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