WHY IN TETRAAMMINECOPPER(2) ELECTRON FRONM LOWER VALENCE 3D SUSHELL PROMOTES TO P ORBITAL OF HIGHER ENERGY TO HAVE DSP2 HYBRIDISATION INSTEAD OF SP3 HYBRIDISATION????? MAIL ME ANSWER AT (iit.aspirants.2010@gmail.com?

Remember hybridization is a theory that allows us to explain an observation. If it is consistent with our observations (tetrammine copper (II) ion is flat) than it is a good theory. In general, hybridization theory predicts electron promotion (which requires energy) to result in a net lowering of energy as a result of bond formation. In the case of Cu2+ an electron is promoted from a 1/2 filled d orbital to form a filled orbital and leaving an empty d orbital which then undergoes hybridization with the empty s and 2 empty p orbitals.