Question

Identify the element so that the last electron enters in ( \(n-2\) )f sub shell.

• A. Au
• B. Hg
• C. W
• D. No

Hint:

Elements in which the last electron enters the (n-2)f subshell are the f-block elements.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept
The last electron enters the \((n-2)f\) subshell in lanthanoids \((4f)\) and actinoids \((5f)\). These are f-block elements.

Step 2: Check Each Option
Au, Hg and W are d-block elements.
No (nobelium, \(Z=102\)) is an actinoid with \(5f^{14}\).

Step 3: Compare the options
Option (D).

Final Answer:
Nobelium is the f-block element in the list. \[ \boxed{\text{(D) }\text{No}} \]