Here we're going to say when group 1A and 2A metals combined with the following anions, they form strong bases. So the anions include hydroxide ion which is OH-, hydride ion, which is H-, the amide ion which is NH2- and the oxide ion which is O2-. The group 1A and 2A metals include we're going to have here lithium, sodium, potassium, rubidium and cesium. And then in Group 2A we're going to have calcium, strontium and barium.
So it's just the ones that I've written in which will be the metals when they combine with these four negative ions will create a strong base. So here for hydroxide. So let's say I took lithium ion and hydroxide ion and then I took calcium ion and hydroxide ion. So remember with charges when the numbers are the same, they cancel out. So this would just be LiOH lithium hydroxide here the numbers are different, There's a 2 here and A1 here. So two would come here and one would come here. That two is for all of the calcium hydroxide. All of the hydroxide ions are to be Ca(OH)2 hydride.
So let's say I took Na+ and H-. Here the numbers are the same, so they just cancel out to give me NaH, which is sodium hydride. Here let's say we had Sr2+ and H-. Again, the numbers are different. When they're different, they crisscross. So 2 from here would come here and one from here would come here to give me strontium hydride. Then we have amide ion. So let's say we did potassium with NH2-. That would give me potassium amide here. If we have barium with the amide ion, the numbers are different. So two would come here and one would come here. So this would be barium amide, so Ba(NH2)2 and then we have oxide.
So let's say we did Cs+ and O2-. The numbers are different. So what happens? They crisscross, one comes here, 2 comes here. So this would be Cs2O cesium oxide. And then let's say we had Ca2+ and O2-. Here the numbers are the same, so they don't crisscross, they just cancel out. So calcium oxide. So here we're just looking at different combinations of the metals that I have from groups 1A and 2A in blue mixed with one of these negative ions. Doing that will form a strong base. Remember, as a result of being a strong base, you are a strong electrolyte.