[name]
Argon
[intro]
Argon with atomic number 18 is part of the noble gases in group 18. It is the third most abundance gas in the earth’s atmosphere, even twice as much then the amount of water vapor.  Argon is named after the Greek word Argos meaning as much as relaxed, lazy or inactive which refers to the inertness of this element. The discovery of Argon is written to Robert John Strutt also known as Lord Rayleigh and Sir William Ramsay, whom both worked at the London university college. 
In 1785 the English physicist Henry Cavendish posted an problem about the observation that after removal of Oxygen and Nitrogen out of liquefied pure air there was an unknown residual material. This triggered Lord Rayleigh hundred years later to do his experiments on air.  
Working on experiments with liquefied clean air they found, in 1895, that after removal of the Oxygen, water vapor and the carbon dioxide the remaining Nitrogen was slightly, 0.5%,  heavier than the Nitrogen that they became after creating it with different types of experiments. After several months they concluded that there had to be another unknown gas in the samples.
Already in 1882 there were rumors of a new element within the research of H.F. Newall and W.N. Hartley who both separately from each other did research at clean air using spectroscopy. They both found spectral lines which they couldn’t refer to the at the time known elements.
Up to 1957 the symbol for Argon was the letter A then they changed it to the to us commonly known symbol Ar.
[image]
This is the current image description