(Jimmy of the Clue Crew indicates the right-hand column of the periodic table.) On the periodic table, the six gases in this column, beginning with helium & ending with radon, are described as this, because they don't readily react with other elements
[DOC] [TLE] Usuario:AVBOT/Reversiones humanas/2009/05/07 - WikiVisually [PAR] May 7, 2009 ... For this reason, they are described as H1N1, H1N2 etc.