On the basis of Valence bond theory account for the hybridization, shape and magnetic property of cuprammonium ion.

Explanation

`Cu^(2+) ………….. [Ar] 3d^9 4s^0`

Under the influence of approaching `NH_3` ligand an `1e^-` from 3d gets excited to 4p.

The four empty orbitals undergo dsp-hybridization to form four hybrid orbitals of equal energy.
The orbitals of the ligand which contain lone pair of electrons overlap with hybrid orbitals `Cu^(2+)` ion to form co-ordinate bond.

Shape ........ squar planar
Or