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The elements

The Group 18 elements have a particular name Noble gases. Noble gas is translated from the German noun Edelgas , first used in 1898 by Hugo Erdmann (1862 - 1910) to indicate their extremely low level of reactivity. The noble gases were often also called the inert gases , however, since noble gas compounds are now known this name is no longer used. [link] lists the derivation of the names of the Noble gases.

Derivation of the names of each of the Group 18(VIII) elements.
Element Symbol Name
Helium He Greek helios meaning the Sun
Neon Ne From the Greek meaning new one
Argon Ar From the Greek meaning inactive
Krypton Kr From the Greek kryptos meaning the hidden one
Xenon Xe From the Greek xenos], meaning foreigner , stranger , or guest
Radon Rn From its radioactive nature

Discovery

Helium

The first evidence of helium was the observation by astronomer Pierre Janssen ( [link] ) on August 18, 1868 as a bright yellow line with a wavelength of 587.49 nm in the spectrum of the chromosphere of the Sun. On October 20 of the same year, English astronomer Norman Lockyer ( [link] ) observed a yellow line in the solar spectrum, which he named the D3 Fraunhofer line because it was near the known D1 and D2 lines of sodium. He concluded that it was caused by an element in the Sun unknown on Earth. Lockyer and Edward Frankland ( [link] ) named the element with the Greek word for the Sun, helios .

Portrait of French astronomer Pierre Jules César Janssen (1824 - 1907).
English scientist and astronomer Sir Joseph Norman Lockyer, FRS (1836 - 1920).
English chemist Sir Edward Frankland, KCB, FRS (1825 - 1899).

On March 26, 1895 British chemist Sir William Ramsay ( [link] ) isolated helium on Earth by treating the mineral cleveite (a radioactive mineral containing uranium and found in Norway) with mineral acids.

Scottish chemist Sir William Ramsay, KCB FRSE (1852 - 1916).

Neon

Neon was discovered in 1898 by Sir William Ramsay ( [link] ) and Morris Travers ( [link] ). When Ramsay chilled a sample of air until it became a liquid, then warmed the liquid and captured the gases as they boiled off. After nitrogen, oxygen, and argon, the three gases that boiled off were krypton, xenon, and neon.

English chemist and founding director of the Indian Institute of Science, Morris William Travers (1872 - 1961).

Argon

In 1785 Henry Cavendish ( [link] ) suspected that argon was present in air but it was not isolated until 1894 by Lord Rayleigh ( [link] ) and Sir William Ramsay ( [link] ) in an experiment in which they removed all of the oxygen, carbon dioxide, water and nitrogen from a sample of clean air.

British scientist Henry Cavendish FRS (1731 - 1810).
English physicist John William Strutt, 3 rd Baron Rayleigh, OM (1842 - 1919).

Krypton

Krypton was discovered in 1898 by Sir William Ramsay ( [link] ) and Morris Travers ( [link] ) in residue left from evaporating nearly all components of liquid air.

In 1960, an international agreement defined the meter (m) in terms of wavelength of light emitted by the 86 Kr isotope (wavelength of 605.78 nm). This agreement replaced the standard meter located in Paris, which was a metal bar made of a Pt-Ir alloy, and was itself replaced by a definition based on the speed of light, a fundamental physical constant. In October 1983, the Bureau International des Poids et Mesures defined the meter as the distance that light travels in a vacuum during 1 / 299,792,458 s.

Questions & Answers

Three charges q_{1}=+3\mu C, q_{2}=+6\mu C and q_{3}=+8\mu C are located at (2,0)m (0,0)m and (0,3) coordinates respectively. Find the magnitude and direction acted upon q_{2} by the two other charges.Draw the correct graphical illustration of the problem above showing the direction of all forces.
Kate Reply
To solve this problem, we need to first find the net force acting on charge q_{2}. The magnitude of the force exerted by q_{1} on q_{2} is given by F=\frac{kq_{1}q_{2}}{r^{2}} where k is the Coulomb constant, q_{1} and q_{2} are the charges of the particles, and r is the distance between them.
Muhammed
What is the direction and net electric force on q_{1}= 5µC located at (0,4)r due to charges q_{2}=7mu located at (0,0)m and q_{3}=3\mu C located at (4,0)m?
Kate Reply
what is the change in momentum of a body?
Eunice Reply
what is a capacitor?
Raymond Reply
Capacitor is a separation of opposite charges using an insulator of very small dimension between them. Capacitor is used for allowing an AC (alternating current) to pass while a DC (direct current) is blocked.
Gautam
A motor travelling at 72km/m on sighting a stop sign applying the breaks such that under constant deaccelerate in the meters of 50 metres what is the magnitude of the accelerate
Maria Reply
please solve
Sharon
8m/s²
Aishat
What is Thermodynamics
Muordit
velocity can be 72 km/h in question. 72 km/h=20 m/s, v^2=2.a.x , 20^2=2.a.50, a=4 m/s^2.
Mehmet
A boat travels due east at a speed of 40meter per seconds across a river flowing due south at 30meter per seconds. what is the resultant speed of the boat
Saheed Reply
50 m/s due south east
Someone
which has a higher temperature, 1cup of boiling water or 1teapot of boiling water which can transfer more heat 1cup of boiling water or 1 teapot of boiling water explain your . answer
Ramon Reply
I believe temperature being an intensive property does not change for any amount of boiling water whereas heat being an extensive property changes with amount/size of the system.
Someone
Scratch that
Someone
temperature for any amount of water to boil at ntp is 100⁰C (it is a state function and and intensive property) and it depends both will give same amount of heat because the surface available for heat transfer is greater in case of the kettle as well as the heat stored in it but if you talk.....
Someone
about the amount of heat stored in the system then in that case since the mass of water in the kettle is greater so more energy is required to raise the temperature b/c more molecules of water are present in the kettle
Someone
definitely of physics
Haryormhidey Reply
how many start and codon
Esrael Reply
what is field
Felix Reply
physics, biology and chemistry this is my Field
ALIYU
field is a region of space under the influence of some physical properties
Collete
what is ogarnic chemistry
WISDOM Reply
determine the slope giving that 3y+ 2x-14=0
WISDOM
Another formula for Acceleration
Belty Reply
a=v/t. a=f/m a
IHUMA
innocent
Adah
pratica A on solution of hydro chloric acid,B is a solution containing 0.5000 mole ofsodium chlorid per dm³,put A in the burret and titrate 20.00 or 25.00cm³ portion of B using melting orange as the indicator. record the deside of your burret tabulate the burret reading and calculate the average volume of acid used?
Nassze Reply
how do lnternal energy measures
Esrael
Two bodies attract each other electrically. Do they both have to be charged? Answer the same question if the bodies repel one another.
JALLAH Reply
No. According to Isac Newtons law. this two bodies maybe you and the wall beside you. Attracting depends on the mass och each body and distance between them.
Dlovan
Are you really asking if two bodies have to be charged to be influenced by Coulombs Law?
Robert
like charges repel while unlike charges atttact
Raymond
What is specific heat capacity
Destiny Reply
Specific heat capacity is a measure of the amount of energy required to raise the temperature of a substance by one degree Celsius (or Kelvin). It is measured in Joules per kilogram per degree Celsius (J/kg°C).
AI-Robot
specific heat capacity is the amount of energy needed to raise the temperature of a substance by one degree Celsius or kelvin
ROKEEB
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Source:  OpenStax, Chemistry of the main group elements. OpenStax CNX. Aug 20, 2010 Download for free at http://cnx.org/content/col11124/1.25
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