Cobalt, with the atomic number 27, has a unique electron configuration that can be visualized using an orbital diagram. The electron configuration for cobalt is 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁷. This means it has 27 electrons distributed among various orbitals.
The orbital diagram for cobalt can be drawn as follows:
1s: ↑↓ 2s: ↑↓ 2p: ↑↓ ↑↓ ↑↓ 3s: ↑↓ 3p: ↑↓ ↑↓ ↑↓ 4s: ↑↓ 3d: ↑↓ ↑↓ ↑↑ ↑
In the diagram:
- The 1s and 2s orbitals each hold 2 electrons, represented by paired arrows (↑↓).
- The 2p orbital has 6 electrons, fully filling the three p orbitals with paired arrows.
- The 3s and 3p orbitals each are fully filled with 2 and 6 electrons, respectively.
- The 4s orbital is filled with 2 electrons before the 3d orbitals due to its lower energy.
- The 3d subshell holds 7 electrons. According to Hund’s rule, the first five d orbitals each get one electron before any pairing occurs, which is why the first five are shown with ↑↑, and then the remaining two get paired up in the first two d orbitals.
This configuration results in cobalt exhibiting properties that are characteristic of transition metals, including its ability to form various oxidation states and complex ions.