The electron configuration of a ground-state Ag atom is
A) [Ar]4s24d9
B) [Kr]5s14d10
C) [Ar]4s14d10
D) [Kr]5s23d9
E) [Kr]5s24d10
The correct answer and explanation is :
The correct answer is A) [Ar]4s²4d⁹.
Explanation:
Silver (Ag) has an atomic number of 47, which means it has 47 electrons in its ground-state configuration. To determine the correct electron configuration, we can follow the Aufbau principle, Hund’s rule, and the Pauli exclusion principle.
- Starting from the core configuration:
Silver belongs to period 5 of the periodic table, and the preceding noble gas in its period is Argon (Ar), which has an atomic number of 18. So, the electron configuration of silver will start with the configuration of Argon:
[Ar]. - Next, we fill the remaining electrons:
After Argon, we begin filling the next available orbitals, which are in the 4th and 5th shells. The sequence of orbitals to fill is 4s, 4p, 4d, and 5s.
- First, we fill the 4s orbital. Since the 4s orbital can hold up to two electrons, we place 2 electrons in the 4s orbital.
- Then, we move to the 4d orbital. The 4d orbital can hold up to 10 electrons, but in the case of silver, it only needs 9 electrons to complete its electron configuration.
- Final Configuration:
Combining the noble gas core configuration and the remaining electrons in the 4s and 4d orbitals, the electron configuration of a ground-state silver atom is:
[Ar] 4s² 4d⁹.
Why not the other options?
- B) [Kr]5s¹4d¹⁰: This configuration corresponds to the electron arrangement for palladium (Pd), not silver. Palladium has atomic number 46, and its 4d subshell is fully filled with 10 electrons (5s¹4d¹⁰).
- C) [Ar]4s¹4d¹⁰: This configuration doesn’t represent silver in its ground state. If the electron were in the 4s¹ orbital, it would imply the atom is in an excited state, not a ground state.
- D) [Kr]5s²3d⁹: This is the electron configuration for copper (Cu), which has an atomic number of 29. Copper’s configuration is [Ar] 4s¹ 3d¹⁰, not this.
- E) [Kr]5s²4d¹⁰: This configuration corresponds to cadmium (Cd), which has an atomic number of 48, and would be incorrect for silver.
Thus, the correct electron configuration for a ground-state silver atom is [Ar] 4s² 4d⁹.