Sec. 1.7] 



PROPERTIES OF NUCLEI 



15 



Table 2. Atomic Weight and Natural Abundance of Isotopes 

 An asterisk (*) indicates that the isotope is radioactive. The relative abundances of 

 most medium and heavy elements are subject to some uncertainty since values reported by 

 various investigators differ by as much as 50 per cent for the rare isotopes and as much as 

 10 per cent for the more abundant. 



