High school senior Jessica Lee dropped a little science in her yearbook quote:
Our readership does not include any chemists (sorry Mark, your bathtub crystal meth operation doesn't qualify you) so you likely don't have the periodic table memorized, making the joke hard to discern.
Still don't get it? Here's a Muppets-style cartoon mashup (featuring NSFW lyrics) to jog your memory.
"Tattoo on tittie sayin' B.I.G." gets me every time.