Fajans-Soddyian displacement theorems
Displacement of cores on the nuclide due to various types of radioactive decay:
vertical: atomic number (number of protons) Z
horizontal: neutron number N
vertical: atomic number (number of protons) Z
horizontal: neutron number N
The Fajans-Soddy shift theorems (also radioactive shift theorems ) are rules established by Kasimir Fajans and Frederick Soddy in 1913 , which describe how the atomic number and mass number of atomic nuclei change when they decay radioactive . The rules later found their explanation with research into the structure of atomic nuclei and the nature of the "decay" processes (more precisely: transformation processes).
- During alpha decay , a nuclide is created with an atomic number two units lower than the parent nuclide. The mass number is reduced by four units.
- During beta decay , a nuclide of the same mass number is created. The atomic number increases (β - decay) or decreases (β + decay and electron capture ) by one unit.
literature
- Kasimir Fajans: The radioactive transformations and the periodic system of the elements . In: Reports of the German Chemical Society . No. 46 , 1913, pp. 422-439 , doi : 10.1002 / cber.19130460162 .
- Frederick Soddy: The Radio Elements and the Periodic Law . In: Chem. News . No. 107 , 1913, pp. 97-99 .
- Frederick Soddy: The Radio-Elements and the Periodic Law . In: Nature . tape 91 , no. 2264 , March 20, 1913, pp. 57-58 , doi : 10.1038 / 091057a0 .