21. "' Noble gas configuration "'is the term given to the electron configuration of noble gases. 22. A colorless, heavy, odorless noble gas , xenon occurs in the Earth's atmosphere in trace amounts. 23. Calculations indicate that radon difluoride may be ionic, unlike all other binary noble gas fluorides. 24. Xenon compounds are the most numerous of the noble gas compounds that have been formed. 25. In his doctoral thesis he described the noble gas filled thermionic converter developed by him. 26. High-order harmonic generation has been observed in noble gas jets, cells, and gas-filled capillary waveguides. 27. Argon is the most abundant noble gas in Earth's crust, comprising 0.00015 % of the crust. 28. The light emission of highly compressed noble gas is exploited technologically in the argon flash devices. 29. "' Noble gas compounds "'are chemical compounds that include an group 18 of the periodic table. 30. Also mention the history of noble gas compounds.
