Answer: J

If you pore over the the Periodic Table of Elements with a keen eye, you’ll notice something peculiar. Some letters appear quite frequently (like R, S, and A), some appear infrequently (like K, V, and Z), but only one letter never makes an appearance. Every single letter is present within the naming conventions of the elements except for the letter J.

How exactly has the letter J been missing all these years? While it might seem almost like some sort of inside joke that the letter has never been used, the reality is altogether more mundane. Historically elements were named using Latin or Greek naming conventions and neither language has a J–thus it’s easy to see why the earliest inclusions on the table were J free. As time went on the naming conventions were relaxed slightly and no longer strictly adhered to the alphabetic sets available in Latin/Greek. At this point it’s only a matter of time before a new element is bestowed a name which a J in it.