The electronic configuration of silver atom in ground state is

The correct option is [Kr]4d¹⁰5s¹.

Let's break down the step-by-step reasoning to determine the ground-state electronic configuration of silver (Ag):

1. Determine the Atomic Number of Silver (Ag):
Silver is a transition metal located in Group 11 and Period 5 of the periodic table. Its atomic number is 47, which means a neutral silver atom has 47 electrons.

2. Identify the Nearest Noble Gas Core:
To write the condensed electronic configuration, we find the noble gas that precedes silver in the periodic table. This noble gas is Krypton (Kr), which has an atomic number of 36. Its configuration represents the first 36 electrons:
[Kr] = 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶

3. Distribute the Remaining Electrons (Aufbau Principle & Exception):
After using the Krypton core, we have 47 − 36 = 11 valence electrons remaining to be distributed in the 5s and 4d subshells.
According to the Aufbau principle, the 5s subshell is filled before the 4d subshell because it has a lower energy level. This would lead to the expected configuration:
[Kr] 4d⁹ 5s²

4. Extra Stability of Fully-Filled Subshells:
However, transition metals often exhibit exceptions to the Aufbau principle due to the extra stability associated with half-filled and fully-filled subshells. A fully-filled d-subshell (d¹⁰) is exceptionally stable because of symmetrical charge distribution and high exchange energy.
To achieve this highly stable state, one electron from the 5s subshell is promoted to the 4d subshell. This shifts the configuration from the expected [Kr] 4d⁹ 5s² to the actual, more stable ground-state configuration:
[Kr] 4d¹⁰ 5s¹