You try! Use the periodic table and what you have learned about oxidation numbers to complete the following electron dot formulas.

  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 charges (oxidation numbers) 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.)

Interactive exercise. Assistance may be required. Directions: Drag the tiles to the correct location to create the electron dot formula. 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. Use the "previous" and "next" buttons to cycle through the six problems.