 Okay, let's try this one. So this one has to do with trends in atomic size You can look at the periodic table and figure out this problem. So the question is asking Put these in order of Size smallest the biggest so Remember well, so these are all alkaline metals all group 1A So if you look at where they are so again the periodic table is your cheat sheet again You look at where they are and you remember that The atom size gets bigger as you go down the periodic table Then you can just look at where they are relative to each other and answer this question so the smallest one is going to be the one that's the highest up and In this case, it's sodium and then the next smallest one of course is potassium And then of course cesium cesium is actually Enormous and that's smallest the biggest