Hi there, my name is Dr. Scott Melidio and in this short under 5 minute video we are going to be covering ionic compounds that have a polyatomic ion in them. The assumptions that I am making in this video are that you already know how to determine the name and formula of a binary ionic compound and the names and formulas for the polyatomics being talked about, which are sulfate, SO4, 2- and phosphate, PO4, 3-. Next we will go from the formula to the name. When naming an ionic compound that has a polyatomic ion, the same rules apply as if you are naming a binary ionic compound with the only exception being you do not change the name of the polyatomic ion if it is an ion. Let's look at the formula, NA2SO4. What would the name be? How does the video to give yourself some time? Did you say sodium sulfate? Yes, great. If not, did you remember that sulfate's name does not change? Next, let's go the other direction and look at the compound named calcium phosphate. Does the video to give yourself some time? Did you write the following? CA3, parentheses, PO4, closed parentheses, 2? Remember if not that the calcium ion is positive 2 and phosphate is minus 3. Also you need the parentheses to show how many phosphates you have without them. This is what it would look like. CA3, PO4, 2, which as you can see is pretty different. We can use either the crossover method or the formula to check our work as shown. Thank you for watching this video. I hope it was helpful. If you watched all my videos related to ionic compound, thank you for spending the time.