Question

Which of the following elements has completely filled 4 f orbital at the expected ground state configuration?

• A. \(\text{La}\)
• B. \(\text{Yb}\)
• C. \(\text{Eu}\)
• D. \(\text{Gd}\)

Hint:

Ytterbium is [Xe] 4f14 6s2.

Answer 1

The Correct Option is B

Step 1: Count 4f electrons
La 0, Eu 7, Gd 7, Yb 14.

Step 2: Compare
Full means 14, which only Yb has.

Step 3: Answer
Option (B).

Final Answer:
Option (B). \[ \boxed{\text{Yb}} \]