题目内容
(1)→_______Pa+
(2)______U→+
(3)→+________
(4)→+________
(1) (2) (3) (4)
(1)Th→________Pa+e
(2)________U→Th+He
(3)Rn→Po+________
(4)Co→Mn+________
完成下列衰变方程: