Up to this point, we know how many oxygens are found within our trioxides and Tetra oxides. Now it's time to take a look at how do we determine their charges. We know that our trioxides are here within this T and we know that they are called trioxides because they have 3 oxygens to them to think about their charges.
There's a pattern when we take a look at the periodic table. So starting with group 3A, we have -3. So this would be BO3-3 or -3. Then we go -2 -, 1. So if -2, all those in Group 4A would be 2 minus and then no three would be -1 O. Here we determine the charges for the trioxides when they end with the name 8, We'll get to that later on with the truettroxides.
The tetraxides here we're going to start over again. So -3 -, 2, -, 1, so -3 here for PO4-3. We've determined that they have 4 oxygens because they're tetraoxides and this would be SO4-2. Notice here we have another slot here for -1, which represents elements within this group 7A. We'll talk about them later on.
So at this point we determine who our trioxides are and who are Tetra oxides are, how many oxygens they have and what their charges are. Now that we've taken a look at these different types of polyatomic ions, let's continue onward and take a look at additional one.