Hate to ruin your fun/logical comment, but "xenon trifluoride undecafluoroantimonate" is actually a compound, not an element. The periodic table has ELEMENTS, not compounds. Based on its name, I can infer that it has the elements xeon, fluorite, and some other random elements INSIDE that compound.
Okay now that I just typed this comment up, it entertained myself a little bit today. So, yeah, I didn't hate to ruin that comment.