Interactive exercise. Assistance may be required. Electron dot structures are used to model ionic bonds. This interactive will show you how to create electron dot structures. Click on the next button to begin the animation.

You try!

Remember to properly write the electron dot formula following the steps below.

  1. List the cation first followed by the anion.
  2. Draw eight dots around the anion to show the completed octet.
  3. Place brackets around each symbol.
  4. Write the charge of each ion outside of the brackets.
  5. Make sure the charges add up to zero. (If the charges don’t add up to zero, add the numbers in front of the brackets to represent how many of each ion would be present in the compound.)

Now let’s practice writing an electron dot formula.

Lithium and oxygen form an ionic bond.

Lithium is in group 1A, so each atom of lithium has one valence electron. This is the Lewis valence electron structure for lithium.

Oxygen is in group 6A, so each atom of oxygen has six valence electrons. This is the Lewis valence electron structure for oxygen.

Interactive exercise. Assistance may be required. Complete the electron dot formula by dragging the tiles to the correct location. Show the correct number of valence electrons for the anion by clicking on the gray circles. Note that not all of the tiles will be used and not all spots will need a tile.