What is the ground state electron configuration for Co3+? [Ar] 3d6 [Ne] 3d4 4s2 [Ar] 3d3 4s2 4p1 [Ar] 3d5 4s1 [Ar] 3d4 4s2
The Correct Answer and Explanation is:
The correct ground state electron configuration for Co³⁺ is:
[Ar] 3d⁶
Explanation
To determine the electron configuration of Co³⁺, we first need to understand the configuration of the neutral cobalt (Co) atom.
Cobalt has an atomic number of 27, meaning it has 27 electrons in its neutral state. The ground state electron configuration for neutral cobalt is:
[Ar] 4s² 3d⁷
This configuration follows the order of electron filling according to the Aufbau principle, where the 4s orbital is filled before the 3d orbital.
Now, to find the configuration of Co³⁺, we must remove three electrons from the neutral atom. Electrons are removed starting from the outermost shell first. Even though the 4s orbital is filled before the 3d orbital, it is higher in energy once electrons occupy the orbitals. So, when removing electrons, they come out of the 4s orbital before the 3d.
Starting with the neutral configuration:
[Ar] 4s² 3d⁷
We remove two electrons from the 4s orbital and one electron from the 3d orbital:
- Remove 2 electrons from 4s² → 4s⁰
- Remove 1 electron from 3d⁷ → 3d⁶
This results in:
[Ar] 3d⁶
This is the electron configuration for Co³⁺ in its ground state.
Now, let’s briefly review the incorrect options:
- [Ne] 3d⁴ 4s²: This configuration is invalid because it refers to an atom with only 10 electrons in the core and is not suitable for a cobalt ion.
- [Ar] 3d³ 4s² 4p¹: This adds up to more electrons than cobalt has, which is incorrect.
- [Ar] 3d⁵ 4s¹ and [Ar] 3d⁴ 4s²: These would correspond to different ions or elements, not Co³⁺.
Therefore, [Ar] 3d⁶ is the correct answer.
