Covalent bonds are formed by the sharing of electrons. How can you tell if a covalent bond is polar or non-polar?

Polarity is determined by each atom's "electron greediness": that is, its ability to attract an electron from its position near the other atom in a bond. This is called electronegativity.

What to do:

I. In the model below, adjust the sliders for the electronegativity of each atom in the covalent bond (white oval). Explore how "electron-greediness" affects electron sharing and bond polarity.

II. Be able to answer the following challenges and questions. Use the model to prepare your answers.

  1. Describe the type of settings that cause a polar bond, that is, a separation of the bond's charge into positive and negative areas.
  2. Explain the cause of the separation of charge in a polar bond.
  3. What types of settings cause a non-polar bond, that is, mild or no separation of positive and negative charge?
  4. The electronegativity of oxygen is 3.5, hydrogen is 2.1, and carbon is 2.4. Which bond is more polar: a carbon-hydrogen bond or oxygen-hydrogen bond?

Note: The colors used to indicate positive and negative charge differ between chemistry and biology activities, as they do in different areas of science. Always check the color key to see what color is positive and what color is negative - it is different in a chemistry page (like this one, where red is positive) and in biology pages (where red is negative)! However, it is often more important to note the amount of separation of charge into positive and negative, that is, the intensity of color, rather than whether it is positive of negative.