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 electronegativity: its ability to attract an electron from another atom.

  

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.

  • Explain the cause of the separation of charge in a polar bond.
  • What types of settings cause a non-polar bond, that is, mild or no separation of positive and negative charge?
  • 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 surface 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 a red surface is positive) and in biology pages (where a red surface 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.

    When you are finished, close this window and return to the activity in the Molecular Workbench.