 So let's do this problem now. So it asks what's the atomic number, the group number, and the period number for each of these elements. So in order to do this problem, well, you're going to have to know what these things are talking about, but you're going to have to have a periodic table associated or available to you, which you probably will anyways. But anyway, so look at the periodic table and the atomic number, it's just the, of course, the number, what order the atom is in. So, for example, calcium, so this is calcium, its atomic number is 20. Silver's atomic number is 47. So arsenic, 33. And then sulfur, of course is 16. Okay, so the group number, that's the number that's on the top of the column. So the column on the periodic table we call groups. Okay, so if we look, the group number for calcium of course is, you can call it either 2a or group 2. Okay, for silver, it's over in the transition metals there. So you see, it's group 1b or 11. Arsenic, it's into the, well, well, we'll talk about this one. I guess you guys don't know about transition metals, main group and stuff yet. But arsenic's over a few more. And you can see its group number is 5a, 15. And then sulfur is 1 over from that, which is 6a or 16. And the period on the periodic table are the roads, are the roads, the roads, the roads. So calcium, you can see, you count them. So there are the number that's on the left of the periodic table, which this is not a periodic table, but. So you just count down, 1, 2, 3, 4. So calcium is in period number 4. Silver, 1, 2, 3, 4, 5. Silver is in period 5. Arsenic, also period 4. And sulfur is 1 period above arsenic in period 3. So again, you have to have the periodic table available to you. But once you have that, it should be fairly straightforward.