What is the electron configuration silver, Ag? *** Exception Ag:
The Correct Answer and Explanation is:
The electron configuration of silver (Ag) is [Kr] 4d¹⁰ 5s¹.
This configuration deviates from the expected order based on the Aufbau principle. Ordinarily, one would predict silver to have the electron configuration [Kr] 4d⁹ 5s², filling the 5s orbital before completing the 4d subshell. However, silver is one of the notable exceptions among transition elements due to the relative stability gained from a fully filled d subshell.
A fully filled 4d¹⁰ configuration is energetically more favorable than a partially filled 4d⁹ with a completely filled 5s². This is largely attributed to the subtle balance between subshell energies and electron-electron interactions. Specifically, a full d subshell exhibits enhanced stability due to factors such as exchange energy and symmetrical electron distribution. Exchange energy is a quantum mechanical phenomenon where electrons with parallel spins in degenerate orbitals (same energy) create a more stable arrangement. In the case of silver, the gain in stability from filling the 4d orbital completely outweighs the cost of promoting one electron from the 5s orbital.
This behavior is not unique to silver. Similar anomalies are observed in copper (Cu) and gold (Au). Copper adopts a configuration of [Ar] 3d¹⁰ 4s¹, while gold has [Xe] 4f¹⁴ 5d¹⁰ 6s¹. These anomalies reflect a broader trend among group 11 elements and highlight the limitations of using a strictly rigid Aufbau sequence without considering stabilizing effects present in specific orbital arrangements.
Recognizing these exceptions is important for understanding the chemical behavior of elements. Silver’s electron configuration plays a role in its ability to form stable +1 oxidation states and its effectiveness in applications such as catalysis and photography. This exception also reinforces the idea that electron configurations are shaped by a combination of principles, not a single rule.
