The Noble Gases, Group 18 of the periodic table, comprise:

1. #4 – Helium (He), from Greek for sun, helios, as it was first identified from sun light.
2. #10 – Neon (Ne), from Greek for new, novum.
3. #18 – Argon (Ar), the Greek word for “lazy”, referring to its inertness.
4. #36 – Krypton (Kr), from Greek for “the hidden one”, krytos.
5. #54 – Xenon (Xe), from Greek for stranger or guest, xenos.
6. #86 – Radon (Rn), from the isotope Rn₂₂₂, which decays from the metallic element Radium.

All of the noble gases are present on Earth, especially in the atmosphere, from which they are isolated by fractional distillation at extremely low temperatures. They are almost completely unreactive with other elements as a result of having their electron shells completely filled.

Argon constitutes almost 1% of the atmosphere, and is the gas inside incandescent light bulbs. Neon and Xenon are used in fluorescent lighting, and helium is readily available at party stores for filling balloons. Because of its short half life, Radon cannot be obtained.

To obtain pure samples of all noble gases, its best to purchase a set. Nova Elements has all the stable elements for about $90 Canadian (US$75, €60). You may also be able to get samples of each from an industrial gas supplier.