Which element was discovered first among the noble gases?

Argon was the first noble gas discovered, identified in 1894 by Lord Rayleigh and William Ramsay. Its discovery changed chemistry by revealing that there was an entirely new family of inert gases. Argon makes up about 0.93 percent of Earth’s atmosphere by volume, so it was present all along but unnoticed. The finding helped complete the modern understanding of the periodic table’s structure.