The transuranium elements

摘要: The place of the very heaviest elements in periodic system is great scientific interest and crucial importance understanding physical chemical properties these elements. Ideas on this question have varied considerably over years. Periodic charts commonly placed thorium, protactinium, uranium positions immediately below hafnium, tantalum, tungsten. latter group are members a transition series which 5d electron shell being filled. Hence earlier placement three heavy corresponded to assumption that they 6d series. Indeed and, much smaller extent, do show considerable resemblance 4d electronic configuration beyond radon core basis would be written thus: thorium (6d 27s 2), protactinium 37s 47s 2).