1. Neutral Chromium's Configuration:
* Chromium (Cr) has an atomic number of 24, meaning it has 24 electrons.
* The standard electron configuration for neutral chromium is: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹ 3d⁵
2. The Exception to the Rule:
* You might notice that the 4s subshell only has one electron instead of two. This is a common exception to the Aufbau principle, which states that electrons fill orbitals in order of increasing energy. In the case of chromium (and copper), a half-filled d-orbital and a fully-filled s-orbital are more stable.
3. Ionization and Electron Removal:
* Chromium(III) ion (Cr³⁺) has lost three electrons. These are removed from the highest energy levels first, so the 4s orbital is emptied and then two electrons are removed from the 3d orbital.
4. Complete Electron Configuration of Cr³⁺:
* 1s² 2s² 2p⁶ 3s² 3p⁶ 3d³
Therefore, the complete electron configuration for chromium(III) ion is 1s² 2s² 2p⁶ 3s² 3p⁶ 3d³.
