Uses of Noble Gases
Helium in balloons, neon in signs and argon in welding and lamps.
Helium in balloons, neon in signs and argon in welding and lamps.
Noble gases are used where chemical inertness or a special physical property is needed rather than reactivity. Helium, far less dense than air, fills balloons and airships, and liquid helium cools the superconducting magnets in MRI scanners. Neon glows bright red-orange when electrically excited, which makes it the familiar gas in advertising signs. Argon provides an inert atmosphere for welding and fills light bulbs, where it slows filament evaporation. Krypton and xenon are used in high-intensity lamps, and radon is a radioactive gas that is a health hazard in buildings.
Key ideas: He: balloons and cryogenic cooling of MRI magnets at 4 K, deep sea diving mixes with O2 to avoid narcosis. Ne: red-orange signs. Ar: inert atmosphere for welding and incandescent bulbs. Kr and Xe: high-intensity lamps, Xe in anesthesia and ion thrusters. Rn: radiotherapy but also hazardous indoor gas. Ar makes up 0.93 percent of air by volume.
Common mistakes and connections: Students say helium is lighter than hydrogen; it is twice the mass of H2, but nonflammable, so preferred for airships. He is not renewable on human timescales, as it escapes Earth. Colors from discharge tubes are atomic emission lines. Links to emission spectra, liquefaction of gases and radioactive decay chain of radon.
Neon has a filled 2p shell; excited by an electric discharge it glows red-orange, while the filled shell makes noble gases chemically inert. The interactive lesson shows this as a live animation or chart.
Liquid helium cools the superconducting magnets of MRI machines to a few kelvin.
Helium in balloons, neon in signs and argon in welding and lamps.
Uses of Noble Gases is a beginner topic in Inorganic Chemistry. It needs no earlier chemistry lessons and is a good starting point.
Study these earlier topics in Inorganic Chemistry first: Bleaching Powder, Noble Gases, Xenon Compounds.
The next topics in Inorganic Chemistry are Transition Metals General and Variable Oxidation States.
Yes. The interactive lesson includes a self-check question on Uses of Noble Gases, and the Inorganic Chemistry quiz draws on every topic in this area.
Uses of Noble Gases is topic 53 of 113 in Inorganic Chemistry.