Identify the element from following such that the last electron is placed in ( n -1 ) d orbital.

Step-by-step solution

The element where the last electron occupies the ( n -1) d orbital can be identified by examining electronic configurations of the given options. The general configuration for d-block elements is ( n -1) d ¹⁻¹⁰ ns ¹⁻² , where n denotes the principal quantum number of the outermost shell. Dysprosium (Dy, Z=66 ) has configuration [ Xe ] 4 f ¹⁰ 6 s ² and is a lanthanide where the last electron enters the 4 f orbital. Silver (Ag, Z=47 ) has configuration [ Kr ] 4 d ¹⁰ 5 s ¹ with outermost shell n=5 . The 4 d orbital co