sulfur Sulfur stinks. If you smell something that stinks, sulfur is likely present. It also provides that wonderful pungency to wasabi or Chinese mustard.
nitrogen
About 4/5 of the air you breath is nitrogen. It is quite inert. It is good to use for creating a non-flammable environment. Of course if you want to live, you should realize you need oxygen there to if you want to be in that environment.
hydrogen
This is the lightest element. It is very reactive with guess what .... oxygen (duh, water). It is very reactive period. I don't know why anyone would think it was a good idea to make a blimp with this
