Write the complete ground-state electron configuration of Ag+.
The Correct Answer and Explanation is:
Complete ground-state electron configuration of Ag⁺ (silver ion):
[Kr] 4d¹⁰
Explanation
To determine the ground-state electron configuration of Ag⁺, we must first understand the configuration of a neutral silver (Ag) atom. The atomic number of silver is 47, which means a neutral Ag atom has 47 electrons.
The electron configuration of neutral silver is:
Ag: [Kr] 4d¹⁰ 5s¹
This configuration may seem unusual because it does not follow the expected pattern of filling orbitals based purely on energy order. Normally, we would expect the 5s orbital to be fully filled before electrons enter the 4d orbital. However, silver is one of those transition metals where a completely filled 4d subshell (with 10 electrons) is more stable than having 4d⁹ 5s². As a result, one electron from the 5s orbital is promoted to the 4d subshell, giving the observed configuration of [Kr] 4d¹⁰ 5s¹.
Now, when silver loses one electron to form Ag⁺, it loses it from the outermost shell, which is the 5s orbital. This is because electrons are always removed from the highest energy level first during ionization, and the 5s orbital has a higher principal quantum number (n = 5) than the 4d orbital (n = 4).
Removing the one electron from 5s¹ gives the electron configuration of Ag⁺ as:
Ag⁺: [Kr] 4d¹⁰
This means that the Ag⁺ ion has a fully filled 4d subshell and no electrons in the 5s orbital. The [Kr] core represents the electron configuration of krypton, the noble gas preceding silver in the periodic table, which accounts for the first 36 electrons. The remaining 10 electrons fill the 4d orbital completely, leading to a particularly stable configuration for Ag⁺.
This fully filled d-subshell contributes to the chemical stability and unique properties of the silver ion.
