Question

Which element would be the most potent oxidizing agent out of scandium and iron, and out of manganese and chromium?

Answer 1

Well which element in each pair has the most valence electrons....?

Explanation:

So for scandium and iron, the choice is clear. and the highest oxidation state I know is `Fe(VI+)`, which is expressed in (the rare) `FeO_4^(2-)`. Scandium forms almost exclusively `Sc(III+)`, complexes, mind you, there are a few novel subvalent `Sc^0`, `Sc^(+)` or `Sc^(2+)` species, and these are exceptionally rare.

For manganese and chromium, we got `Mn(VII+)` in `Mn_2O_7`.....I have never used this but it is apparently a volatile liquid; of course, it is a potent oxidant. `Cr(VI+)` is present in `CrO_3` and `CrO_4^(2-)`...all of these species are used as oxidizing agents....

Answer 2

The oxidation state of any element in its free state is zero, but `"Mn"` and `"Fe"` are tied for the highest observed oxidation states in their compounds.

Explanation:

Are you asking about the highest known oxidation state of these elements in their compounds?

Manganese

The electron configuration of `"Mn"` is `"[Ar] 4s"^2 "3d"^5`.

The most common oxidation states of `"Mn"` in its compounds, are +2, +3, +4, +6, and +7.

Since `"Mn"` has seven valence electrons, +7 is its highest possible oxidation state, as in the purple permanganate ion, `"MnO"_4^"-"`.

Chromium

The electron configuration of `"Cr"` is `"[Ar] 4s 3d"^5`.

The most common oxidation states of `"Cr"` in its compounds, are are +2, +3, and +6.

Since `"Cr"` has six valence electrons, +6 is its highest possible oxidation state, as in the yellow chromate ion, `"CrO"_4^"2-"` and the orange dichromate ion, `"Cr"_2"O"_7^"2-"`.

Scandium

The electron configuration of `"Sc"` is `"[Ar] 4s"^2 "3d`.

The most common oxidation state of `"Sc"` in its compounds is +3.

Since it has three valence electrons, +3 is its highest possible oxidation state, as in scandium(III) chloride, `"ScCl"_3`.

Iron

The electron configuration of `"Fe"` is `"[Ar] 4s"^2 "3d"^6`.

The most common oxidation states of `"Fe"` in its compounds are +2 and +3.

Its highest oxidation state is +7, as in the extremely rare `"FeO"_4^"-"` ion.

Chromium

The electron configuration of `"Cr"` is `"[Ar] 4s 3d"^5`.

The most common oxidation states of `"Cr"` in its compounds, are +2, +3, and +6.

Since it has six valence electrons, +6 is its highest oxidation state, as in the yellow chromate ion, `"CrO"_4^"2-"` and the orange dichromate ion, `"Cr"_2"O"_7^"2-"`.