ARGON, HELIUM, KRYLON, NEON, RADON XENON.
The gases in this category are odorless, colorless and monatomic, with low chemical reactivity.
In contrast, hydrogen that is the most abundant in our universe, as monatomic H, is chemically reactive.
The proportions in our universe for hydrogen, helium and oxygen are 1818 : 14 : 1, nearly.
