[Co(NH3)5Cl]Cl2 is paramagnetic.
To determine whether a coordination compound is paramagnetic or diamagnetic, you need to consider the number of unpaired electrons in the central metal ion's electronic configuration. In this case, the central metal ion is cobalt (Co).
Cobalt (Co) has an atomic number of 27, and its electronic configuration is: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁷
In [Co(NH3)5Cl]Cl2, the cobalt ion (Co²⁺) loses two electrons, so its electronic configuration becomes: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁵
The 3d subshell of cobalt has 5 electrons, and since it has unpaired electrons, the complex is paramagnetic. Paramagnetic compounds have one or more unpaired electrons, making them attracted to a magnetic field.