Science, Tech, Math › Science Noble Gases List Share Flipboard Email Print Xenox is a noble gas we encounter daily in the headlights of cars. bizoo_n / Getty Images Science Chemistry Periodic Table Basics Chemical Laws Molecules Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated September 14, 2019 The elements in the last column or group of the periodic table share special properties. These elements are noble gases, sometimes called inert gases. Atoms belonging to the noble gas group have completely filled their outer electron shells. Each element is non-reactive, has high ionization energy, electronegativity near zero, and a low boiling point. Moving down the group in the periodic table from top to bottom, the elements become more reactive. While helium and neon are practically inert and are gases, the elements further down the periodic table more readily form compounds which are more easily liquefied. Except for helium, all of the names of the noble gas elements end with -on. Elements in the Noble Gas Group Helium (He, atomic number 2) is an extremely light, inert gas at room temperature and pressure. The liquid form of the element is the only liquid known to man that cannot be solidified, no matter how low the temperature drops. Helium is so light it can escape the atmosphere and bleed away into space.Neon (Ne, atomic number 10) consists of a mix of three stable isotopes. The element is used to make signs and gas lasers and as a refrigerant. Neon, like helium, is inert under most conditions. However, neon ions and unstable clathrates are known. Like all noble gases, neon glows a distinctive color when excited. The characteristic reddish-orange glow of signs comes from excited neon.Argon (Ar, atomic number 18) in nature is a mixture of three stable isotopes. Argon is used in lasers and to provide an inert atmosphere for welding and chemicals, but it can form clathrates and has been known to form ions. Argon is heavy enough that it doesn't readily escape Earth's gravity, so it is present in appreciable concentrations in the atmosphere.Krypton (Kr, atomic number 36) is a dense, colorless, inert gas. It's used in lasers and lamps.Xenon (Xe, atomic number 54) in nature consists of a mix of stable isotopes. The pure element is inert and non-toxic, but it forms compounds that may be colored and are toxic because they display strong oxidizing tendencies. Xenon is encountered in everyday life in xenon lamps such as strobe lamps and some vehicle headlamps.Radon (Rn, atomic number 86) is a heavy noble gas. All of its isotopes are radioactive. Although colorless under ordinary conditions, radon is phosphorescent as a liquid, glowing yellow and then red.Oganesson (Og, atomic number 118) presumably would behave like a noble gas but would be more reactive than the other elements in the group. Only a few atoms of oganesson have been produced, but it is believed that it will be a liquid or solid at room temperature. Oganesson is the element with the highest atomic number (mostly protons) on the periodic table. It is extremely radioactive.