 Okay, so using the periodic table, rank each of these main group elements according to decreasing atomic size. Calcium, magnesium, and strontium. Okay, so decreasing, that means biggest to smallest, right? So which one's the biggest, the biggest one? Strontium's the biggest. Calcium. Calcium and then very magnesium. Right, so they're all in the same group, right? They're just one below the next one. Okay, so big, smaller, smallest. Okay, that's the trend of the periodic table. Everybody okay with that? Any questions on that?