FTP, name this noble gas with atomic number 18 and chemical symbol Ar.
Combined with thorium, this element is used in lamps for wavelength calibration. Researchers at the University of Helsinki have gotten it to form a compound with hydrogen and fluorine, and it was discovered in 1894 by Lord Rayleigh and William Ramsay. Its unreactivity is due to the 6 electrons that fill its 3p subshell, and it is an alternative to nitrogen because it will not conduct heat as well from tungsten filaments in light bulbs. FTP, name this noble gas with atomic number 18 and chemical symbol Ar.
Combined with thorium, this element is used in lamps for wavelength calibration.
Argon