Electronic configuration of copper.Atomic number of Cu = 29 { 1s }^{ 2 }{ 2s }^{ 2 }{ 2p }^{ 6 }{ 3s }^{ 2 }{ 3p }^{ 6 }{ 4s }^{ 1 }{ 3d }^{ 10 } or {Ar}{4s}^{1}{3d}^{10} Electron from 4s shifts into 3d orbit for stabilization. Attains stabilization with half filled and full filled orbit.