Which element belongs to the f-block? oxygen iron argon uranium

The answer to your question is: Uranium.

Explanation:

Elements of the f-block are the elements of the inert earth transition metals. They the located in 2 rows beow the other elements in the periodic table. They included lathanides and actinides.

Oxygen belongs to the p-block, so it is not oxygen the answer.

Iron belongs to the d-block. This is incorrect.

Argon belongs to the p - block, this option is incorrect.

Uranium belongs to the f-block.