Question

Which of the following actinoids exhibits only +3 oxidation state?

• A. Lr (z = 103)
• B. U (z = 92)
• C. Th (z = 90)
• D. Pa (z = 91)

Hint:

The actinides typically exhibit a range of oxidation states, but some, like Lawrencium, have only one.

Answer 1

The Correct Option is A

Step 1: Understanding oxidation states.
Lr (Lawrencium) is an actinide element that exhibits only a +3 oxidation state. Other elements in the actinide series can exhibit multiple oxidation states, including +4, +5, and +6.

Step 2: Analyzing the options.
(A) Lr (z = 103): Correct — Lr typically exhibits a +3 oxidation state.
(B) U (z = 92): Uranium can exhibit oxidation states of +3, +4, +5, and +6.
(C) Th (z = 90): Thorium can exhibit oxidation states of +3 and +4.
(D) Pa (z = 91): Protactinium can exhibit oxidation states of +3, +4, and +5.

Step 3: Conclusion.
The correct answer is (A) Lr as it exhibits only the +3 oxidation state.