Polar Bonds and Molecules Notes

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 H2O

4

• We can show this with arrows to represent the
  direction or flow of electrons. This small
  positive and negative charge is labeled as d
  (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

• Van der Waal forces- the attractive or repulsive
  force between moleculesm
• 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

8
(No Transcript)
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 (d) and the other element (d-).
10
Hydrogen Bond