Cobalt has 3 electron shells (or rings) in its atomic structure.

Here's why:

* Atomic Number: Cobalt's atomic number is 27, which means it has 27 protons and 27 electrons.

* Electron Configuration: The electron configuration of cobalt is 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁷. This configuration shows how the electrons are arranged in different energy levels:

* 1st Shell: 2 electrons (1s²)

* 2nd Shell: 8 electrons (2s² 2p⁶)

* 3rd Shell: 17 electrons (3s² 3p⁶ 4s² 3d⁷)

Therefore, cobalt has 3 electron shells.