21. Noble gases , caesium and iodine were absent, signifying their volatilization from the hot material.22. The noble gases up to xenon have multiple stable isotopes. 23. Like the other noble gases , krypton is highly chemically unreactive. 24. For example, unreactive gases ( e . g . noble gases ) formed one column. 25. Many tiny cells between two panels of glass hold an inert mixture of noble gases . 26. The lighter noble gases ( helium through argon ) do not form stable binary fluorides. 27. The heavier noble gases ( krypton, xenon ) are the rarest stable elements on Earth. 28. The noble gases have full valence electron shells. 29. The inertness of noble gases makes them very suitable in applications where reactions are not wanted. 30. His doctoral thesis dealt with the effects of Zeeman effect on spectral lines of noble gases .
