An element with an extremely long half-life.

An element found in conjunction with tin, forming a lumpy, jelly-like consistency. Found in Barking and the Canary Isles.

An element whose physical and chemical properties are hard to fathom.

An element placed with a cat in a sealed box.

The fifth isotope of Symphonium, discovered in early 19th century Germany, but in a bizarre irony, it's first practical use was as part of the United Kingdom's war machine in world war two.