As the official administrators of the Periodic Table, the good people at IUPAC are pleased to share their intimate knowledge of its most arcane history and structural details, such as why plutonium’s symbol is Pu rather than Pl, or where you might be able to find some of the synthetic radioactive element americium at home. If you’d like to peek into the nooks and crannies of this definitive database, take the challenge they have just launched to test your knowledge.