DISINTEGRATION OF RADIUM 



57 



active nucleus is one which spontaneously changes itself into another 

 nucleus of another element by emitting a charged particle. 



Radon gas is a short-lived residue which rapidly disintegrates with 

 the liberation of alpha particles and changes into a solid, radium A. 

 In turn, this element breaks up into radium B in an analogous way. 

 These and subsequent decomposition products are found adhering to 

 the walls of a vessel which originally contained radon gas and which 

 make these surfaces radioactive. 



88 Atomic number 



c trnnc Very strong 



-ybtrong 7 Includes groups 214 & 210 



214 



214 \ 

 0.04%\ 



a. 214 \ 



y \ y ""* ^7 



Polonium 

 84 



Weak 



/3 -/RaD V/*-/ RaEV/?{ RaF 

 210 210 



n 



Stable lead RaG 

 isotope ^ J 



4 206 



Natural alpha particle = 2 He .Charge +2, mass units 4. 



Fig. II— 1. Radium and its family of products. 



Radium B, however, undergoes a different type of change, one accom- 

 panied by the emission of a gamma radiation and of a high-speed beta 

 particle. Since the gamma ray is a short-wave x-radiation, its emission 

 results in no appreciable loss in mass. The beta particle is a high-speed 

 negative electron. The ejection of such an electron is accompanied by 

 an inappreciable loss in atomic mass; the new element, radium C, is 

 therefore considered as having the same atomic mass as its parent atom 

 radium B. 



Biophysically speaking, this and the next group of radioactive nuclear 



