 Xenon was discovered in England by the Scottish chemist William Ramsay and English chemist Morris Travers in September 1898 , shortly after their discovery of the elements krypton and neon . They found xenon in the residue left over from <unk> components of liquid air . Ramsay suggested the name xenon for this gas from the Greek word <unk> [ xenon ] , <unk> singular form of <unk> [ <unk> ] , meaning ' foreign ( er ) ' , ' strange ( r ) ' , or ' guest ' . In 1902 , Ramsay estimated the proportion of xenon in the Earth 's atmosphere as one part in 20 million . 
