Ions, electrons, and ionizing radiations / by James Arnold Crowther.
- James Arnold Crowther
- Date:
- 1919
Licence: Public Domain Mark
Credit: Ions, electrons, and ionizing radiations / by James Arnold Crowther. Source: Wellcome Collection.
245/300 page 225
![CHAPTER XIV RADIUM AND ITS PRODUCTS 119. The nature and properties of radium. The prin- ciples we have been considering will be made clearer, and the evidence for them more conspicuous, if we study in detail one series of radio-active changes. That of radium is the most suitable for the purpose, not merely on account of its intrinsic importance but also owing to various accidental] causes which render the phenomena particularly clear. Radium can be isolated from uranium ores, in which it exists as a product of the radio-active disintegration of the uranium. It is obtained by the processes used in the extraction of barium from the ores, to which element it bears a close chemical resemblance. It can be obtained free from barium by repeated fractional crystallization of the bromide, the radium salt being somewhat less soluble in water than the corresponding salt of barium, with which, however, it is isomorphic. The proof of the elementary nature of radium is now com- plete. It is afforded, in the first place by the spectrum, which is characteristic of the metal, and differs from those of all other elements. The lines in the radium spectrum have now been analysed into their component series, and are found to present the common characteristics of the metals of the alkali earths. Applying the usual laws of spectra the spectrum of radium is found to correspond to that of an alkali earth metal of atomic weight about 225. Radium has now been obtained in sufficient quantities and of sufficient purity to enable its atomic weight to be obtained by direct chemical methods. The method employed is that of precipitating the radium chloride with silver nitrate, and weighing the silver chloride formed. By repeated crystallization Madame Curie obtained a product so pure that the strongest](https://iiif.wellcomecollection.org/image/b32782032_0245.jp2/full/800%2C/0/default.jpg)
