Syllabus     |   |     Next Section

Learning Plan

  1. Watch the video on writing formulas for simple ionic compounds.

  2. Review Essential Information on formula writing for simiple ionic compounds.

  3. Correctly write the formula for ten simple ionic compounds in a row!

Once you get ten in a row, return to the Syllabus or continue to the next section Naming Ionic Compounds with Transition Metals.

Essential Information

Writing Formulas for Binary Ionic Compounds:

  • Write the symbols for each element.
  • Find the charge for each element using the Periodic Table. Write it above each element.
  • See if the charges are balanced (if they are you're done!)
  • Add subscripts (if necessary) so the charge for the entire compound is zero.
  • Use the crisscross method to check your work.
  • Don’t write the subscript '1'.
  • If you use the criss-cross method and end up with something like Ca2S2 you'll need to reduce the subscripts to Ca1S1 which we write as CaS.