The spin-only magnetic moment value of M^n+‑ ion formed among Ni, Zn, Mn and Cu that has the least enthalpy of atomisation is_____. (in nearest integer)
Here n is equal to the number of diamagnetic complexes among K₂ [NiCl₄], [Zn (H₂O)₆] Cl₂, K₃[Mn(CN)₆] and [Cu(PPh₃)₃I]