One of these elements is the main component of the mixture ionized by radiation in a Geiger counter.
A Penning mixture is mostly composed of one of these elements, and the decay of one of these elements' isotope-40 to its isotope-39 is used in a namesake type of radioactive dating. One of these elements is the main component of the mixture ionized by radiation in a Geiger counter. An alpha particle is the nucleus of one of these elements, and all of these elements have complete octets. For 10 points, name this group of very non-reactive elements including xenon, argon, and helium.
A Penning mixture is mostly composed of one of these elements, and the decay of one of these elements' isotope-40 to its isotope-39 is used in a namesake type of radioactive dating.
Noble Gases