The ground-state electron configuration of the In+ ion is [Kr]4d^10 5s^2 [Kr]5s^2 [Kr]4d^10 5s^2 5p^3
The Correct Answer and Explanation is:
The correct ground-state electron configuration for the In⁺ ion is:
[Kr] 4d¹⁰ 5s²
Explanation:
To determine the configuration of the In⁺ ion, we begin with the electron configuration of a neutral indium (In) atom. Indium has an atomic number of 49, which means it has 49 electrons. The electron configuration of neutral indium follows the Aufbau principle, which fills orbitals in order of increasing energy. This gives:
In: [Kr] 4d¹⁰ 5s² 5p¹
This notation indicates that indium’s valence shell includes the 5s and 5p orbitals. The 4d orbital is completely filled and more stable, so electrons are not removed from it unless absolutely necessary.
The In⁺ ion has a +1 charge, which means one electron has been removed from the neutral indium atom. Electrons are first removed from the highest energy orbital. In this case, that would be the 5p orbital, not the 5s or 4d orbitals. Therefore, the single 5p electron is removed, resulting in:
In⁺: [Kr] 4d¹⁰ 5s²
This configuration reflects a fully filled 4d subshell and a filled 5s subshell, creating a relatively stable electron arrangement. The 5s orbital is slightly lower in energy than 5p, so it remains occupied when only one electron is lost.
Other answer choices like [Kr] 2d¹⁰ 5s² are incorrect because no 2d orbital exists. Similarly, [Kr] 5s² ignores the stable 4d electrons, and [Kr] 4d¹⁰ 5s² 5p³ suggests additional electrons rather than a loss. Therefore, [Kr] 4d¹⁰ 5s² is the most accurate representation of the In⁺ ion’s ground-state configuration.
