Argon
Argon is a type of chemical element with an Ar symbol and an atomic number 18. It is located in a group of 18 periodic tables. Argon is the third most abundant gas in Earth's atmosphere; it forms 0.93% of the atmospheric content. The content of the argon in the atmosphere is about 23.8 times more than the 4th largest gas in the atmosphere, carbon dioxide, and more than 500 times more than the fluorescent gas. Almost all of the argon gas in the atmosphere is a radiogenic argon-40, which results from potassium-40 decay in the crust of the Earth. The most common argon isotopes around the universe are argon-36, because these isotopes are most often produced by the nuclear synthesis of the stars in the supernova. The name "argon" is derived from the Greek word, αργον meaning "lazy" or "inactive". This is related to the nature of argon which almost does not have any chemical reaction. Octet petals whose fullest outer atom makes the element's atom stable and does not bind chemically with other elements. Its triple point temperature at 83.8058 K is a fixed point of refinement within the International Temperature Scale of 1990.