How does the shape of a molecule affect its polarity?

Answer 1

shape determines everything. You need to know something about hybridization to determine a molecules shape. for instance, H2O is two single covalent bonds of H to O. O also has two orbitals with paired electrons not bonded to anything. this causes the hybridiztion of O in this case to be sp3 which is always in a tetrahedral shape. hard to visualize without a reference. see a gen chem book. Anyway, because of the molecules hybridization, it is bent like a boomerang with the partially positive H's at the ends of the boomerang and the partially negative O at the apex of the boomerang. like this ^. if you drew a line horizontally through this boomerang, the positive charge would be on the botom and the negative charge would be on top. H2O is a polar molecule because of its shape. CO2 is linear with a C in the middle and 2 O's on either side opposing eachother. the C is sp hybridized because the bonds to each O are double bonds. sp hybridization makes a linear shape. both partially negative O's are on either side cancelling their charges. CO2 is a non-polar molecule because of its shape.

Answer 2

In a molecule, usually there are elements that are more electronegative than others. The electronegative elements attract the electrons more strongly and have a partial negative charge. Depending on the shape of the molecule it is either polar or non-polar. For example, in carbon dioxide the oxygen atoms are more electronegative and have a partial negative charge. However, the two oxygen atoms are placed on opposite sides so the effects cancel eachother out and the molecule is not polar. In water, the molecule is bent and the oxygen is more electronegative, so the overall effect is the electrons are pulled away from the hydrogen atoms in a specific direction. This means that water is polar and that the negative end of one molecule can be attracted to the positive end of another molecule, which leads to stronger intermolecular attraction. This is part of the reason why water is usually a liquid and carbon dioxide is usually a gas.

Answer 3

It affects the distribution of electrical charge across the whole molecule. For example: water, H-O-H. Water is not just in a "straight line," but is in a boomerang,
Consider carbon dioxide, O=C=O. The molecule is linear. There are charge differences between carbon and oxygen, but the symmetry of the molecule cancels them out. Carbon dioxide is nonpolar.