Hevesy, G. von

Handbook der Physik, Vol. XXX. Rbntgenstrahlen, Julius Springer, Berlin, 1957. G. von Hevesy, Chemical Analysis by X-rays and Its Applications, McGraw-Hill Book Co., New York, 1932. 

G. von Hevesy and E. Alexander, Praktikum der ehemischen Analyse mil Rontgen-strahlen, Akademische Verlagsgesellschaft, Leipzig, 1933. 

G. von Hevesy, Chemical Analysis by X-rays and Its Applications, Chapter 9. 

When H. G. ]. Moseley discovered the simple relationship which exists between the X-ray spectrum of an element and its atomic number, there were seven unfilled spaces in the periodic table. Elements 43, 61, 72, 75, 85, 87, and 91, were yet to be revealed. Element 91 (protactinium) was discussed with the radioactive elements in Chapter 29. In 1923 D. Coster and G. von Hevesy showed that element 72, hafnium, is widely distributed but that it had escaped detection because of its close resemblance to zirconium. Element 75 (rhenium) was announced by W. and l. Noddack in 1925, and is now a commercial article. 

G. von Hevesy obtained greater yields of potassium by the electrolysis of its hydroxide than of sodium with its hydroxide at the same temp. For example, between 320° and 340°, a 27 per cent, yield of sodium, and a 55 per cent, yield of potassium, were obtained. This was traced to the increased rate of diffusion of sodium from cathode to anode where the metal is lost by secondary reactions and this the more, the higher the temp. F. C. Wickel and W. Lobel obtained potassium from its hydroxide and metallic sodium, by melting the two together in the absence of air sodium oxide is formed and potassium distils from the mixture hydrogen gas also escapes. 

Disco very 0/ phenomenon of induced or artificial radioactivity) 2)G.von Hevesy H.Levi, KglDanskeVidenskabSelskabMatfys Medd 14, 5(1936) 3)0.Hahn, "Applied... 

Hafnium Hf 72 Dirk Coster,G.von Hevesy Denmark Latin name "Hafnia" meaning "Copenhagen"... 

After helium and argon had been discovered the existence of neon, krypton, xenon, and radon was clearly indicated by the periodic law, and the search for these elements in air led to the discovery of the first three of them radon was then discovered during the investigation of the properties of radium and other radioactive substances. While studying the relation between atomic structure and the periodic law Niels Bohr pointed out that element 72 would be expected to be similar in its properties to zirconium. G. von Hevesy and D. Coster were led by this observation to examine ores of zirconium and to discover the missing element which they named hafnium. 

G, von Hevesy, Ueher die schmelzelektrolytische Ahscheidung der AlhalimetaUe aus Aetzedkalien und die LosUchkeit dieser MetaUe in der Schmelze, Froihurg i. Br., 1908 R. Lorenz, Zeit. Elektro-chem., 13. 582, 1907. 

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