 OK, let's try this one. This one just follows those rules that we just talked about, about atoms wanting to obey the octav rule. So remember that wherever you are on the periodic table, it kind of determines whether you want to go backwards or forwards in gaining or losing electrons. So all you've got to do, again, is just look at the periodic table as your cheat sheet here. And it'll tell you what the most probable charge is. So you look at the number of valence electrons each of these has. So let's just do that. If it would be easier for me to get to 8 or 0, or easier for the particular atom to get to 8 or 0. So how many valence electrons does potassium have? Well, 1. Calcium's got 2. Aluminum's got 3. So remember, we want to have a full octet, or have no valence electrons, or 8 valence electrons. We'll do it the way you want to look at it. Bromine's got 7. Sulfur has 6. And phosphorus has 5. So this is kind of a really good problem. So you can see, and in fact, metals or halogens or whatever, they all obey essentially the same principle. So they all have the same number of valence electrons. So they're all going to make essentially the same. So anyways, let's go with that assumption and say, well, is it easier to get to 8 or 0? So 0 will say 2 minus 12. You don't have a 1. OK, so here.