1. Polar Bonds and Molecules Notes

2. Bond Polarity The bonding pairs of electrons are pulled in a tug-of-war between the nuclei of the atoms sharing the electrons. When the atoms pull evenly, the bonding electrons are shared evenly and the bond is a nonpolar covalent bond. Examples: diatomic oxygen, nitrogen, and chlorine.

3. When covalent bonds join two atoms of different elements and the bonding electrons are not shared equally, the bond is a polar covalent bond. Example: HCl and H 2 O

4. We can show this with arrows to represent the direction or flow of electrons. This small positive and negative charge is labeled as δ (delta). It is not a full +1 or –1 charge. A molecule that has two poles is called a dipolar molecule, or dipole.

5. There are several kinds of attractions between molecules: 1.Van der Waal forces- the attractive or repulsive force between moleculesmm –Two Types: Dipole-Dipole Interaction London Dispersion Forces

6. Dipole-Dipole interaction - The electrostatic attractions that occur between the oppositely charged regions of a dipole.

7. London Disperson Forces Dispersion- caused by the motion of the electrons, the more electrons the more force. A molecule with more electrons has a stronger attraction force Weakest type of intermolecular attraction

9. Hydrogen Bond Strongest type on intermolecular attraction When hydrogen bonds to a very electronegative element, it has a strong dipole, therefore allowing for a fairly strong bond between the hydrogen (δ+) and the other element (δ-).

10. Hydrogen Bond