What is the only letter not on the Periodic Table of Elements?
Well, they announced the names of the four new elements this month and if you're hoping "J" was finally going to make it onto the table, think again. The new elements are nihonium (Nh), moscovium (Mc), tennessine (Ts) and oganesson (Og). In some countries, the element "iodine" is known by the name jod but the periodic table still uses the IUPAC symbol "I" for it which makes J the only letter not on the periodic table, at all. Period. Seems random, right? Not really. The elements were originally named using Latin or Greek naming conventions and "J" is not in either language. Source: Chemistry.about.com