How many elements are in the noble gases group?

The noble gases are the elements in Group 18 of the periodic table, and the classic set includes helium, neon, argon, krypton, xenon, and radon. They are known for being extremely unreactive because their outer electron shells are full. Oganesson, element 118, is also placed in Group 18, but it is so short-lived and unusual that its chemistry is still an active research topic. Noble gases have important uses, from neon signs to argon shielding in welding and helium in balloons and cryogenic systems. Radon is radioactive and can build up indoors in poorly ventilated spaces.