Evaluation Methods. Several studies from around the world that have evaluated Incredible Years components meet the Promising Practices Network (PPN) criteria and have found Incredible Years to be a promising or proven program. These studies are listed below, by the component that was tested in the study.
The noble gases (arranged in order of increasing atomic weight) are helium, neon, argon, krypton, xenon and radon. Helium, neon and argon are the three noble gases with the lowest atomic masses. Helium, Neon, Argon. Helium, neon, and argon are the three lightest members of the noble  gases. Hydrogen is the lightest of all elements. According to the Periodic  Table, its atomic weight is 1.00794 u, even lighter than helium.
Over 13 billion years since the Big Bang, hydrogen and helium still make up most of the visible matter in the universe. Nearly 10,000 galaxies appear in this Hubble Ultra Deep Field image. Enlarge Photo credit: NASA, ESA, and N. Pirzkal (STScI/ESA). The Big Bang also churned out helium, the next lightest element.