Eduprobe
Question:
Which of the following exhibits only +3 oxidation state?
Ac
U
Pa
Th
Solution:
The atomic number of Ac is 89. Electronic configuration = [Rn]6d¹7s². The stable oxidation state → +3
Th = +3, +4
Pa = +3, +4, +5
U = +3, +4, +5, +6
Hence, option A (Ac) is correct.