Explain the hybridisation, geometry and magnetic property of `[Ni(Cl)_(4)]^(2-)`.

Explanation

The central metal is present in this complex is Ni (II) or `Ni^(+2)`. Atomic number of Nickel is 28. 
Electronic configuration of `Ni^(+2)` is `[Ar]3d^8 4s^(0)`

One vacant 4s-orbital and three vacant 4p-orbitals hybridize to give four equivalent sp3 hybrid orbitals, oriented tetrahedrally in space.

Each `CI^(-)` ligand donates a pair of electron to form a tetrahedral complex. 

`Sp^3`-hydridisation.
Orbials containing unpaired electrons hence it is paramagnetic.