To understand the electron configuration and orbital diagrams for a chromium atom (Cr) and its chromium III ion (Cr³⁺), we first need to look at their electron configurations.
Chemical symbol for Chromium: Cr
The atomic number of chromium is 24. In its neutral state, chromium has an electron configuration of:
Cr: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁵ 4s¹
For the orbital diagram of neutral chromium, we represent the filled and half-filled orbitals. The 3d subshell is particularly interesting because it is half-filled, which contributes to chromium’s stability:
1s: ↑↓ 2s: ↑↓ 2p: ↑↓ ↑↓ ↑↓ 3s: ↑↓ 3p: ↑↓ ↑↓ ↑↓ 3d: ↑ ↑ ↑ ↑ ↑ 4s: ↑
Now, when we look at the chromium III ion (Cr³⁺), it means chromium has lost three electrons. The electrons are removed first from the 4s orbital and then from the 3d orbitals:
Cr³⁺: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d³
For the orbital diagram of the chromium III ion, we show the remaining occupied orbitals after the removal of electrons:
1s: ↑↓ 2s: ↑↓ 2p: ↑↓ ↑↓ ↑↓ 3s: ↑↓ 3p: ↑↓ ↑↓ ↑↓ 3d: ↑ ↑ ↑
In conclusion, we can clearly see that for Cr, the 4s and 3d orbitals are involved, while for Cr³⁺, only the 3d orbitals remain occupied, showing a reduction in electron count. This illustrates the significance of electron configurations in understanding the behavior of different oxidation states of an element.