Noble+Gas+Discovery

How Were Noble Gases First Discovered?
Helium: Atomic Number: 2 Atomic Mass: 4.0g In 1868, two scientists were using spectroscopes to discover an unknown element in the sun. Their names are Janssen and Lockyear. The element that they discovered was helium, named after the Greek term "helios" translating to mean sun. Helium is now known to be the second lightest and second most abundant gas in the known universe. Hydrogen is the lightest and most abundant gas in the known universe. Since there was no known compound containing helium, scientists believed that helium was incapable to form bonds. The only way to obtain helium is to go through the process of liquefaction of air or separate it from deposits of natural gases. Terrestrial helium is thought to be the product of alpha decay from radioactive isotopes beneath the crust. Soon after discovering helium, other noble gases were discovered. Due to a full outer valence electron shell in these elements, it was believed that noble gases were unable to form bonds. This property is known as being inert. There are a few noble gases that contain compounds that have been discovered, and most of those that have been discovered are unstable. The first compound to contain a noble gas was discovered in 1962 and contained xenon. However, there are no compounds that contain helium. Helium is known to be the only element that will not become a solid by being cooled. It has 98% of the lifting power of hydrogen without any Hindenburg-type drawbacks and is what airships use today.
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Neon: Atomic Number: 10 Atomic Mass: 20.2g In 1898, scientist Ramsay and Travers discovered the fourth most abundant element in the known universe. This element is known as Neon. From the Greek term"neos" translating to mean new, Neon is the fifth most abundant element in the Earth's atmosphere. Known preferably as the gas in Neon Lights, which are actually made up of other gases. Neon has no known stable compounds and can be extracted from air through liquefaction.

Argon: Atomic Number: 18 Atomic Mass: 39.9g In 1894, scientists Rayleigh and Ramsay found the third most abundant gas in the Earth's atmosphere by isolating it. This gas, like other noble gases, is colorless, tasteless, and orderless. For these properties, Argon was named after the Greek term "argos" meaning inactive. Now Argon is most commonly used in ordinary incandescent light bulbs because it can replace the oxygen needed, which would shorten the time usage of the filament. Argon is used in black lights (UV lamps) because when Argon is overexcited it will produce ultraviolet radiation. Argon is also used in welding, when active atmospheric gases are also used in the process. Only a few compounds have been made with Argon, but none of them are stable.

Krypton: Atomic Number: 36 Atomic Mass: 83.8g In 1898, Krypton had been discovered by two scientists, Ramsay and Travers. It is the sixth most abundant element in Earth's atmosphere and can be isolated from other elements through the process of liquefaction of air. Used in many types of lights, ranging from the light bulb used in small flashlights to certain strobe lights used in airport runways. One unusual fact about Krypton that makes it much different than the other noble gases are that its' non-radioactive isotope, Kr-86 is used as the definition of the international meter. One meter is equivalent to 1,650,762.73 wavelengths of Krypton-86's red-orange spectral line.

Xenon: Atomic Number: 54 Atomic Mass: 131.3g In 1898, Ramsay and Travers discovered the noble gas Xenon. From the Greek term "xenos" translating to mean strange, is known as the rarest stable noble gas in Earth's atmosphere. Isolated through liquefaction, this noble gas is most commonly used in strobe lamps. In 1962 Neil Bartlett discovered the first noble gas compound, which contains Xenon, Platinum, and Fluorine. After that discovering it was known that Xenon compounds could be produced if the oxidation state ranged from +2 to +8.

Radon: Atomic Number: 86 Atomic Mass: 222.0g In 1900, Friedrich and Dorn discovered radon. Radon was originally named after the Greek term "niton" meaning shining. However, after it was known that it came from decay of underground deposits of Radium (and Uranium), its' name was changed to Radon.This is a radioactive noble gas and is stated to be a potential health hazard in some homes and is used in some cancer treatments. Radon is another noble gas that can produce a compound. Radon fluoride is that compound and when in its' solid state of matter will glow a yellow light.

__**//Context//**__
 * Chapter on Periodic Table
 * Properties of Elements
 * Discussion on the Noble Gas Family

//**__Follow-Up Questions__**//
 * What are some compounds that contain Noble Gases?
 * What are the gases in Neon Lights?
 * Why do those gases glow?
 * Why does the oxidation state affect the production of Xenon compounds?
 * How is the process of liquefaction of air done?

__**//Sources//**__ http://www.3rd1000.com/elements/noble.htm http://www.dayah.com/periodic/