Chemical Bonding: Polarity

Polarity of Water Molecule

Many molecules have a negative side (pole) and a positive (pole). These are called polar molecules. Nonpolar molecules have a uniform charge (no + or – poles). Polarity helps use understand how molecules will interact with each other. For example, the strands of your DNA are held together because polar molecules.

  • Polarity is the result of more electronegative atoms sharing bonding electrons unequally.
  • The more electronegative atom is slightly negative since the electron (which has a negative charge) is around it more. The less electronegative atom is therefore slightly positive.
  • If a molecule is symmetrical the differences will cancel out and the bond will be non-polar (e.g. CH4).
Video: Polarity (from IssacsTeach)