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Group 18: Noble gases

Updated: Oct 3, 2020

Elements in this group are called Noble gases or inert gases because their outermost shell has completed its octet ie the shell has 8 electrons except Helium which has 2 electrons still it is complete and hence these elements don't participate in any reaction.


 

Helium(He)


Helium is one of the inert or noble gases. Its outside electron shell is filled with electrons. This makes it very nonreactive and non-flammable and doesn’t essentially form chemical compounds.

Checkout the Blog: Colorful Chemistry Beautiful Science of the Periodic table to know the importance of terms you need on the given picture.

Physical properties:


  • At room temperature Helium is colorless, odorless, tasteless and non toxic gas.

  • The density and viscosity of helium vapor are very low.

  • The thermal conductivity is exceptionally high.


Chemical properties:


  • It is less soluble in water as compare to other gases.

  • It can be liquefied below its critical temperature.

  • It has very low boiling and melting points,so that it is generally found in the gas phase except under the most extreme of conditions.

  • Its condensation temperature is the lowest among all the known substances.


Occurrence:


Helium is the second most abundant element in the universe, but on earth, it is very rare. Most people guess that we extract helium from the air, but actually we dig it out of the ground. The main helium source in the world is a series of fields of natural gas notably in Texas, in the United States.

Uses:


  • Helium is used in balloons and airships to make them float. It is not as light at hydrogen, but is a much safer gas as hydrogen is very flammable.

  • The largest industrial user of helium gas is MRI scanners which use the gas to keep the superconducting magnets cool.

  • It is used as protective gas for arc welding.

  • It is used as pressurizing gas in liquid propellants for rockets.

  • Helium-oxygen mixtures in scuba air tanks to dilute the oxygen for divers.

  • as working fluid in nuclear reactors and electronic circuits to cool down by gas.

  • as gas carrier in chemical analysis by gas chromatography.

Discovery:


Helium was first discovered in 1868 by French astronomer Jules Janssen. He noticed the new element when studying a solar eclipse in Guntur in India. The element wasn't found on Earth until 1895. Helium gets its name from the Greek word "helios" meaning "sun".


Fascinating facts:


  • The helium in cylinders is produced by the natural decay of radioactive elements in the earth’s crust mainly thorium and uranium.

  • Helium was discovered in the Sun’s atmosphere before it was found on Earth.

  • if it got inhaled by humans it causes high voice along with other side effects like dizziness, suffocation etc.


 

Neon(Ne):


Neon is the second-lightest noble gas, its color is reddish-orange in a vacuum discharge tube and in neon lamps. The the refrigerating capacity of Neon is over 40 times the one of liquid helium and three times that of liquid hydrogen (on a per unit volume basis). It is a less expensive refrigerant than helium in most applications.

Checkout the Blog: Colorful Chemistry Beautiful Science of the Periodic table to know the importance of terms you need on the given picture.

Physical properties:


  • At room temperature Neon is colorless, odorless, tasteless and non toxic gas

  • It produces bright orange -red glow when electric current passes through it.


Chemical properties:


  • It is soluble in water.

  • It is chemically unreactive.

  • It has very low melting point and boiling point.


Occurrence:

Neon is usually found in the form of a gas with molecules consisting of a single Neon atom. Neon is a rare gas only traces of it is found in the Earth's atmosphere and earth crust. It can be produced commercially from liquid air through a process called fractional distillation.



Uses:

  • It is used in making neon advertising signs.

  • It is used to make high-voltage indicators, lightning arrestors, wave meter tubes, and TV tubes.

  • Neon and Helium are used in making gas lasers.

  • Liquid neon is an economical cryogenic refrigerant.

Discovery:

Neon was discovered by William Ramsay and Morris Travers in 1898. While experimenting on liquid air, They warmed liquefied air and captured the gases that came off it as it boiled. They discovered three new elements including krypton, neon, and xenon. Neon was the second element they discovered.

Fascinating facts:


  • Neon gas is used primarily to light up glass tubes in advertising displays.

  • The gas that makes Las Vegas shine is one of the noble gases, that is Neon.


 

Argon(Ar):


Argon is the third element of the eighteenth column of the period table. It is classified as a noble gas. The argon atom has 18 electrons and 18 protons. Its outer shell is full with eight electrons.


Checkout the Blog: Colorful Chemistry Beautiful Science of the Periodic table to know the importance of terms you need on the given picture.

Physical properties:


  • At room temperature Argon is colorless, odorless, tasteless and non toxic gas

  • It produces bright violet glow when electric current passes through it.


Chemical properties:


  • It is soluble in water just like oxygen.

  • It is chemically nonreactive.

  • It has very low melting point and boiling point.


Occurrence:


This gas is isolated through liquid air fractionation since the atmosphere contains only 0.94% argon. Argon is also found in small traces in the Earth's crust and ocean waters. It constitutes nearly 1% (0.94%) of the volume of air making it the third most abundant element in air after nitrogen and oxygen.

Uses:


  • Argon does not react with the filament in a light bulb even under high temperatures, so is used in lighting.

  • It is particularly important for the metal industry, as an inert gas shield in arc welding and cutting.

  • it is used primarily ice coring.

  • It has also been used for ground water dating.

  • It is also used in technical SCUBA diving to inflate the dry suit, due to its nonreactive, heat isolating effect.

Discovery:


Argon was suspected to be present in air by Henry Cavendish in 1785 but wasn't discovered until 1894. In 1894 English scientist Lord Rayleigh and Scottish chemist Sir William Ramsay began to run experiments on the other gases in air. They eventually discovered argon as well as most of the other noble gases. The name argon comes from the Greek word "argos" meaning "lazy" or "inactive."

Fascinating facts:


  • Argon as the gap between the panes of glass provides better insulation because it is a poorer conductor of heat than ordinary air.

  • The most exotic use of argon is in the Tyre of luxury cars.

  • When argon is used as a gas laser it emits a blue-green color.

 

Krypton(Kr):


Krypton is the Fourth element of the eighteenth column of the period table. It is classified as a noble gas. The Krypton atom has 36 electrons and 36 protons. Its outer shell is full with eight electrons.


Checkout the Blog: Colorful Chemistry Beautiful Science of the Periodic table to know the importance of terms you need on the given picture.

Physical properties:


  • At room temperature Krypton is colorless, odorless, tasteless and non toxic gas

  • It produces bright smoky white glow when electric current passes through it.


Chemical properties:


  • It is highly volatile hence readily escaped in atmosphere.

  • It is chemically nonreactive.

  • It has very low melting point and boiling point.

  • It only reacts with fluorine gas.

Occurrence:


Krypton is one of the rarest gases in the Earth’s atmosphere. It makes up just 1 part per million by volume. It is extracted by distillation of air that has been cooled until it is a liquid.

Uses:

  • Krypton is used commercially as a filling gas for energy-saving fluorescent lights.

  • It is also used in some flash lamps used for high-speed photography.

  • krypton react with fluorine to form krypton fluoride. Krypton fluoride is used in some lasers.


Discovery:


It was discovered in 1898 by William Ramsay and his assistant Morris Travers. The element’s name is given from the Greek word ‘kryptos’ meaning ‘hidden.’

Fascinating facts:


  • From its discovery in 1898 until the 1960 most scientists believed it was impossible to make compounds of krypton, or any other noble gas. Although Krypton difluoride was made in 1963. It is a white, crystalline solid, stable at temperatures below -30 oC.


 

Xenon(Xe):

Xenon element, a heavy and extremely rare gas of Group 18 (noble gases) of the periodic table. It was the first noble gas found to form true chemical compounds.

Checkout the Blog: Colorful Chemistry Beautiful Science of the Periodic table to know the importance of terms you need on the given picture.

Physical properties:


  • At room temperature Xenon is colorless, odorless, tasteless and non toxic gas

  • It produces bright blue glow when electric current passes through it.

  • Solid xenon belongs to the face-centered cubic crystal system, which implies that its molecules, consist of single atom, behave as spheres packed together as closely as possible.


Chemical properties:


  • It is highly volatile hence readily escaped in atmosphere.

  • It is chemically nonreactive.

  • It has very low melting point and boiling point.

  • It only reacts with fluorine gas.


Occurrence:


Xenon is present in the atmosphere at a concentration of 0.086 parts per million by volume. It can also be found in the gases that evolve from certain mineral springs. It is obtained commercially by extraction from liquid air.

Uses:

  • Xenon is used in Xenon lamps as high-speed electronic flash bulbs used by photographers.

  • It is used in sunbed lamps and bactericidal lamps used in food preparation and processing.

  • Xenon lamps are also used in ruby lasers.

  • Xenon ion propulsion systems are used by several satellites to keep them in orbit, and in some other spacecraft.

  • Xenon difluoride is used to etch silicon microprocessors.

  • It is also used in the manufacture of 5-fluorouracil, a drug used to treat certain types of cancer.


Discovery:


It was discovered in 1898 by William Ramsay and his assistant Morris Travers. The name xenon is derived from the Greek word xenos, “strange” or “foreign.”

Fascinating facts:


  • Xenon is More than 4.5 times heavier than air.

  • It is not itself toxic, but its compounds are highly toxic because they are strong oxidizing agents .

 

Radon(Rn):


Radon (Rn) is a radioactive, that occurs naturally as the decay product of the elements radium, uranium and thorium. It is a noble (or inert) gas, meaning it is inactive chemically and combines with other substances only under extreme conditions.


Checkout the Blog: Colorful Chemistry Beautiful Science of the Periodic table to know the importance of terms you need on the given picture.

Physical properties:


  • It is colorless, odorless and tasteless gas.

  • It does not have stable form.

  • Radon dissolves in water and becomes a clear, colorless liquid below its boiling point.

  • Liquid radon freezes as a solid and its color changes from yellow to orange-red as the temperature is lowered even further.


Chemical properties:


  • It is highly volatile hence readily escaped in atmosphere.

  • It is chemically nonreactive.

  • It has very low melting point and boiling point.

  • It combines with other substances only under extreme conditions.


Occurence:


Radon (Rn) is a radioactive, that occurs naturally as the decay product of the elements radium, uranium and thorium.


Uses:

  • Radon is mainly used as a radioactive label to study surface chemical reactions and to initiate reactions.


Discovery:


It was discovered in 1900 by Fredrich E. Dorn. He called it "radium emanation" because the gas came from the radium sample he was studying but the name changed to radon, after the discovery of radium, one of its sources.

Fascinating facts:


  • Radon is a naturally occurring radioactive gas which may be found in indoor environments such as homes, schools, and workplaces.

  • Radon is the most important cause of lung cancer after smoking. .

 


Oganesson(Og) :


Scientists think it would be liquid at room temp but it may be a nonreactive noble gas.


Checkout the Blog: Colorful Chemistry Beautiful Science of the Periodic table to know the importance of terms you need on the given picture.

Physical properties:


  • It is predicted that it may be solid with very high reactivity or it can be a noble gas.


Chemical properties:


  • It may be a radioactive substance with high reactivity.


Occurence:


Oganesson was first produced by a team of Russian and American scientists who smashed californium and calcium atoms together at the joint institute for Nuclear Research in Dubna, Russia.


Uses:


  • It may use as radioactive element like Radon.


Discovery:


It is discovered by the nuclear physicist Yuri Oganessian, a key player in the discovery of the heavy new elements of the periodic table in 2006 by the researchers at the Joint Institute for Nuclear Research (JINR) in Dubna, Russia. It is named oganesson after him in his honor.

Fascinating facts :


  • It is possibly a semiconducting noble gas, most scientists predict the element will be a liquid or solid at room temperature. If the element is a gas, it would be the densest gaseous element, even if it is mono-atomic like the other gases in the group. Oganesson is expected to be more reactive than radon.

 


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