The unexpected E⁰ values for Mn, Ni, and Zn are linked to their electronic configurations. The stability of half-filled d subshell (d⁵) in Mn²⁺ and completely filled d subshell (d¹⁰) in Zn is related to their E⁰ values, while for ...

The decreasing tendency in E⁰ values for M²⁺/M reflects a trend towards less negative values across the transition metal series, which is associated with the increase in the sum of the first and second ionization enthalpies.

Noble transition metals are unaffected by single acids due to their low reactivity. In contrast, most first-series metals, excluding copper, are more reactive and undergo oxidation by 1M H⁺, albeit sometimes at a slow rate.

Oxygen’s ability to stabilize high oxidation states surpasses that of fluorine, as seen in the highest fluoride (MnF₄) and oxide (Mn₂O₇) of manganese, highlighting oxygen’s superiority in forming multiple bonds to metals.

The highest known oxide for iron is Fe₂O₃, and no higher oxides are known beyond Group 7. Although ferrates (VI) are formed in alkaline media, they readily decompose to Fe₂O₃ and O₂.