Neutrogen

Neutrogen is a mixture on Neutronium and Hydrogen, it has an atomic mass of 1.004, in the 1st period and the 0th group. Mot much in known about Neutrogen because it is so rare that it is only made in labs, the nucleous is unique, because it doesnt even have an electron, only a single proton. It was discovered in 1964 by scientist Dorothy Crowfoot Hodgen.

Fun Fact: You can find Neutrogen Water (Hn2O)