[" Hence,no "a" -d-inansition can occure nging onic radius of "Cr^(2+)" is greater than that of "Cu^(2+)],[" Q.3.Atomic radius of Cu is greater than that of "Cr" but ionic radius of "Cr^(2+)" is greater than that of "Cu^(2+)],[" Give suitable explanation."],[" Ans.In Cu,all the d-electrons are paired "(3d^(10)4s^(1))." In Cr,all the "d" -electrons are unpaired "(3d^(5)4s^(1)" ).Hence "],[" delebetern repulaisions in Clu are poind gover then there in Cr.Therefore.Cu atom is large the "]