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Understanding the Unpaired Electron in Permanganate (MnO??)
Understanding the Unpaired Electron in Permanganate (MnO??)
Permanganate, represented chemically as MnO??, is an ion with a -1 formal charge. This ion plays a significant role in chemistry, especially in redox reactions. To fully understand the concept of unpaired electrons in permanganate, it’s essential to examine the valence electron configuration and distribution within the ion.
The Valence Electron Configuration of MnO??
Manganese (Mn) has 7 valence electrons, and each oxygen (O) atom has 6 valence electrons. Therefore, the total number of valence electrons in a MnO? molecule, without considering the charge, would be 31 (7 from Mn 6 from each of the 4 oxygen atoms).
However, since permanganate is -1 ion, it has one additional electron, bringing the total number of valence electrons to 32. This additional electron is achieved by adding the -1 charge to the 31 valence electrons, which directly adds one electron to the system.
Evaluating the Electron Distribution
With 32 valence electrons, the question arises: is there an unpaired electron in the MnO?? ion? To address this question, we need to consider the electron distribution around the manganese atom and the four oxygen atoms.
Typically, the central manganese atom gains and loses electrons according to its valency or oxidation state. In the permanganate ion, manganese takes an oxidation state of 7, which means it has lost a total of 4 electrons: one from each oxygen atom.
Valence Electrons Distribution and Unpaired Electrons
When manganese has a 7 oxidation state, it forms five covalent bonds, each with one of the oxygen atoms. Let's distribute the valence electrons around the manganese and the oxygens.
Manganese (Mn)
Manganese in the 7 oxidation state has lost 4 electrons, meaning it now has 3 valence electrons (3 from the original 7 minus 4 lost electrons).
Oxygen (O) Atoms
Each oxygen atom in the permanganate ion typically shares two electrons with manganese, resulting in the following distribution:
Each of the 4 oxygen atoms in MnO?? shares 2 electrons with manganese, providing a total of 8 electrons. This leaves 24 electrons to be distributed among the 4 oxygen atoms (32 total - 8 from Mn equals 24).Electron Distribution on Oxygen Atoms
Each oxygen atom will have 6 valence electrons (its 4 non-bonded electrons and 2 electrons from its bond with manganese), making the electron configuration for each oxygen atom as follows:
Oxygen (O): 6 valence electrons with 2 paired and 2 unpaired, and 2 from its bonding with manganese.Considering the total configuration, all 32 electrons are paired up except for the 2 unpaired electrons on each of the oxygen atoms.
Conclusion
Therefore, in the permanganate ion (MnO??), the unpaired electrons are actually on the oxygen atoms, not the manganese atom. Each oxygen atom has 6 valence electrons, with 2 unpaired and the remaining 4 being paired.