What is the ground-state electron configuration for the Mn4+ ion and is it paramagnetic or diamagnetic? Group of answer choices [Ar] 3d2, paramagnetic [Kr] 5s2, paramagnetic [Ar] 3d3, paramagnetic [Ar] 4s2 3d5, paramagnetic [Ar] 3d3, diamagnetic [Ar] 3d2, diamagnetic [Ar] 4s2 3d5, diamagnetic
The Correct Answer and Explanation is:
Correct Answer:
[Ar] 3d3, paramagnetic
Explanation:
Manganese (Mn) has an atomic number of 25, which means a neutral manganese atom has 25 electrons. To determine its ground-state electron configuration, we follow the order of electron filling based on energy levels.
The full ground-state electron configuration of neutral Mn is:
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁵
This can be abbreviated using the noble gas argon (Ar), whose electron configuration ends at 3p⁶. So we write:
[Ar] 4s² 3d⁵
Now, we consider the Mn⁴⁺ ion. This means the atom has lost four electrons.
Electrons are removed first from the outermost shell, which includes the 4s orbital and then the 3d orbital.
Mn has:
- 2 electrons in 4s
- 5 electrons in 3d
Removing four electrons total:
- First remove 2 electrons from 4s → [Ar] 3d⁵
- Then remove 2 electrons from 3d → [Ar] 3d³
So the configuration for Mn⁴⁺ is:
[Ar] 3d³
To determine whether the ion is paramagnetic or diamagnetic, we need to consider unpaired electrons.
A 3d³ configuration has three electrons in the d orbitals, each occupying a separate orbital due to Hund’s rule. This means there are three unpaired electrons, making the ion paramagnetic because paramagnetism arises from the presence of unpaired electrons which interact with magnetic fields.
In contrast, diamagnetic substances have all electrons paired and do not exhibit magnetic behavior.
Therefore, Mn⁴⁺ with the configuration [Ar] 3d³ is paramagnetic due to the presence of unpaired electrons in the d orbitals.
