This Excel file, (expires 6/19) allows the student to practice writing formulas for ionic compounds formed from ions in main groups 1-3 with important polyatomic ions. Recommend that students first use the general ionic compounds version first before this version. This is a helpful exercise for ionic compounds containing polyatomics like sulfate, nitrate, phosphate, acetate, hydroxide, and hydrogen carbonate.. Note that the formatting is unique to Excel, and so the student must open as an Excel file. If the file is not opened in Excel, cells will not turn colors as designed. Students must know the charges on the cations for each row and the anions for each column from their textbook or teachers lesson, and then write the formula for each combination (42) of cation and anion. The teacher can use this to demonstrate to the class by projecting to a screen. This basic exercise is a formative assessment designed for the student needing practice just writing formulas with immediate feedback, allowing the student to correct their work. An example is provided. Students know that they should answer in the yellow cells and if they are correct, the cell turns color (as long as the spreadsheet is open in Excel). If the cell doesn't turn color, their answer is incorrect and they need to correct. A running total of correct answers and percent correct is displayed. A teacher can easily look at the colorful displays and see which students are progressing and which students may need help. When complete, the student needs to save the file and submit to the teacher if they are to receive credit. There is a learning curve in these types of exercises for the student and teacher to be comfortable with the process of working with technology, but that is in my opinion a bonus outcome for these exercises. This exercise is appropriate for high school chemistry. I anticipate creating another version with transition metals.