The electronic configuration of atoms and ions is based on the arrangement of electrons in various energy levels and sublevels. The configuration is typically denoted by the principle energy level (n), the type of orbital, and the number of electrons in that orbital.
A. Iron (Fe)
i. In its neutral state, Iron (atomic number 26) has the electron configuration:
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁶
ii. In its ion state, it's common for Iron to lose two or three electrons to form Fe²⁺ or Fe³⁺, respectively.
- For Fe²⁺, the electron configuration would be: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁶
- For Fe³⁺, the electron configuration would be: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁵
B. Chromium (Cr)
i. In its neutral state, Chromium (atomic number 24) has a slightly unusual electron configuration due to electron configurations being more stable when half-filled or fully-filled. This results in the electron configuration:
1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹ 3d⁵
ii. In its ion state, Chromium typically forms Cr²⁺ or Cr³⁺ ions.
- For Cr²⁺, the electron configuration would be: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁴
- For Cr³⁺, the electron configuration would be: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d³