知識(shí)貝殼
知識(shí)貝殼
A group of 15 ra-dioactive elements whose electronic configu-rations display filling of the 5f level. As withthe lanthanoids,the first member,actinium,has no f electrons (Ac[Rn]6d17s2) but othermembers also show deviations from thesmooth trend of f-electr ......（本文共 904 字 ） [閱讀本文] >>