Why is it easier to oxidise Fe^(2+) to Fe^(3+) than it is to oxidise Mn^(2+) to Mn^(3+)?
1 Answer
Well, consider the NEUTRAL electron configurations:
"Fe": [Ar] 3d^6 4s^2
"Mn": [Ar] 3d^5 4s^2
The
"Fe"^(2+): [Ar] 3d^6
"Mn"^(2+): [Ar] 3d^5
Drawn out:
"Fe"^(2+): ul(uarr darr)" "ul(uarr color(white)(darr))" "ul(uarr color(white)(darr))" "ul(uarr color(white)(darr))" "ul(uarr color(white)(darr))
"Mn"^(2+): ul(uarr color(white)(darr))" "ul(uarr color(white)(darr))" "ul(uarr color(white)(darr))" "ul(uarr color(white)(darr))" "ul(uarr color(white)(darr))
A single oxidation is the act of singly ionizing:
"M"^(2+) -> "M"^(3+) + e^(-)
The electron to be removed from
Therefore, it is easier to ionize