NOBLE GASES

The Actinides are a set of 15 highly radioactive elements, only 5 of which can be found in nature. We don't recommend the finding thing: Chernobyl. Their atomic numbers range from 89 to 103, which means rather than living in the main body of the Periodic Table, they get their own row, below. Like that one entitled sibling who gets the en-suite. Uranium92 was the heaviest element known to woman: until 1940, when Neptunium was discovered.

A perfect example of a friend who never has time for you, Sir William Ramsay from Glasgow dedicated his life to discovering Noble Gases. Starting in 1895, he discovered 4 out of 7 gases and was no fun at dinner parties, unless your only interest is Chemistry too. I know you're wondering: Neon lights were invented in 1910. Turns out adding voltage makes Noble Gases unstable after all!