Question

The correct statement(s) about actinides is/are:

• A. The 5f electrons of actinides are bound less tightly than the 4f electrons.
• B. The trans uranium elements are prepared artificially.
• C. All the actinides are radioactive.
• D. Actinides do not exhibit actinide contraction.

Hint:

Actinides are all radioactive, and their 5f electrons are less tightly bound than the 4f electrons of lanthanides.

Answer 1

The Correct Option is A, B, C

Step 1: Analyze the Properties of Actinides.
- (A) The 5f electrons of actinides are more loosely bound compared to the 4f electrons of lanthanides due to the larger size of the actinides.
- (B) The trans-uranium elements (elements with atomic number greater than uranium) are indeed prepared artificially in laboratories.
- (C) All actinides are radioactive, as they have unstable nuclei.
- (D) Actinide contraction is observed, similar to lanthanide contraction, due to the poor shielding of the 5f electrons.

Step 2: Conclusion.
The correct statements are (A), (B), and (C). Therefore, the correct answers are (A), (B), and (C).

Final Answer: \[ \boxed{(A) \text{ The 5f electrons of actinides are bound less tightly than the 4f electrons} (B) \text{ The trans uranium elements are prepared artificially} (C) \text{ All the actinides are radioactive}} \]