Answer:-

Iron (Fe) can exhibit two common oxidation states: +2 (ferrous) and +3 (ferric). Let’s write their electronic configurations and then discuss which one is more stable and why.

1. Iron in the +2 Oxidation State (Fe²+):

   • The electronic configuration of neutral iron (Fe) is: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁶.
   • When iron loses two electrons to form Fe²+, its electronic configuration becomes: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁶.

2. Iron in the +3 Oxidation State (Fe³+):

   • The electronic configuration of neutral iron (Fe) is the same as mentioned above: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁶.
   • When iron loses three electrons to form Fe³+, its electronic configuration becomes: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁵.

Now, let’s discuss which of these two oxidation states (+2 or +3) is more stable for iron:

• The stability of different oxidation states depends on the balance between the electrostatic attraction of the nucleus for electrons and the repulsion between electrons.
• In general, a half-filled or fully-filled electron subshell is more stable due to electron-electron repulsion and exchange energy considerations, which can lead to greater stability.

In the case of Fe²+:

• The 3d subshell has six electrons, leaving it half-filled. This configuration is relatively stable.
• It has one unpaired electron in the 3d subshell, which contributes to its magnetic properties.

In the case of Fe³+:

• The 3d subshell has five electrons, making it nearly half-filled but with one unpaired electron.
• While Fe³+ has a higher positive charge, the electronic configuration is not as stable as that of Fe²+.

Based on the electronic configurations and stability considerations, Fe²+ (iron in the +2 oxidation state) is more stable than Fe³+ (iron in the +3 oxidation state). This stability arises from the half-filled 3d subshell in Fe²+, which results in lower electron-electron repulsion and greater stability compared to the partially filled 3d subshell in Fe³+.