Why does an inert gas show color

Big Bang HTL 2, textbook

44 Area Fundamentals of Chemistry (2nd year, 3rd semester) 3.4.5 The loners - noble gases The noble gases helium, neon, argon, krypton, xenon and radon form the 18th group or the 8th main group of the periodic system. They have the electron configuration s 2 p 6 in their outermost shell. This means that the respective shell is fully filled, and this is what gives the noble gases their outstanding properties. Noble gases prefer to stay alone, ie as atomic gases: individual He atoms, individual Ne atoms, etc. This also earned them the “noble” name: In this context, noble means something like “not getting involved with others want ”, just as the former noble ladies and gentlemen did not want to get involved with the common people. (F26) Noble gases therefore form almost no compounds; it was not until 1962 that a compound of a noble gas was first established, namely XePtF 6 (xenon hexafluoroplatinate). Noble gases are found as natural components of the air, with argon by far the most common (0.934% by volume of the air). The noble gases are extracted from this air. Noble gases are used technically primarily in gas discharge lamps. These are gas-filled tubes with a built-in cathode and anode. When a certain voltage is applied, the gas is made electrically conductive, “ionized” and this leads to luminous phenomena. Neon shows red light, xenon bluish-white. The discharge lamps known as “neon tubes” in everyday life do not contain neon, but mercury vapor and are coated on the inside with a fluorescent substance (usually halophosphate, which is calcium halophosphate doped with Sb 3+ or Mn 2+). A real neon tube glows red (F27, F28). What is “noble” about a noble gas? Where are neon and xenon used? What color does a neon tube shine in? F26 F27 F28 Fig. 3.15: Real neon tubes Xenon is often used in car headlights because the discharge spectrum is similar to that of daylight. 3.4.6 Rare earths The rare earth metals include the lanthanoids and the elements of the 3rd subgroup. The name is confusing in that the rare earth elements are not all that rare. The rarest rare earth element, thulium, is still more abundant than gold. The name comes from the fact that these metals are not found in large deposits, but occur everywhere in small quantities. Scattered all over the world, so to speak. These metals are often used unconsciously in everyday life: many of them are part of computer screens and touchscreens. Recently these elements have come under increasing criticism, as they are almost never recycled and are obtained under inhumane and highly polluting conditions. Fig. 3.16: Xenon car headlights illuminate the road better. Rare earths Write down all elements that belong to the rare earths L Research the Internet about 2 metals of the rare earths, their occurrence, their properties and areas of use. 3.4.6 F29 A1 F30 B1 For testing purposes only - property of the publisher öbv

Made with FlippingBook