Question

Identify general electronic configuration exhibited by \(2^{\text{nd}}\) series of transition elements.

• A. \([\text{Ar}] 4d^{1-10} 4s^2\)
• B. \([\text{Kr}] 4d^{1-10} 5s^{0-2}\)
• C. \([\text{Xe}] 4d^{1-10} 4s^2\)
• D. \([\text{Rn}] 4d^{1-10} 6s^2\)

Hint:

The second series fills 4d with 5s outer electrons, after krypton.

Answer 1

The Correct Option is B

Step 1: Locate the Series:
Second row d-block elements sit in period 5. The noble gas core of period 4 is Kr, and the valence electrons are in 4d and 5s.

Step 2: Range:
The 4d count goes from 1 (Y) to 10 (Cd), and 5s from 0 (Pd) to 2.

Step 3: Answer:
Option (B).

Final Answer:
Option (B). \[ \boxed{\text{(B) } [\text{Kr}]\,4d^{1-10}\,5s^{0-2}} \]