Valence electronic configuration Cu+2 is (29Cu)

Explanation

The valence electronic configuration of Cu+2 is derived from the neutral atom of copper (Cu), which has an atomic number of 29. The electronic configuration of neutral copper (Cu) is 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹ 3d¹⁰. When copper loses two electrons to form the Cu+2 ion, the two outermost electrons from the 4s orbital are removed. Therefore, the valence electronic configuration of Cu+2 is 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁹.Cu is an element of d-block. Its electronic configuration is anomalous owing to the stability associated with half filled and as in the case of Cu, completely filled d-subshell. One electron from the 4s subshell jumps to 3d subshell, thereby making the electronic configuration:1s2, 2s2, 2p6, 3s2, 3p6, 4s1, 3d10Now, for the formation of Cu2+ ion, the Cu atom must lose 2 electrons from the highest energy level. The important thing here is that the 4s orbital of an atom usually fills before electrons go into its 3d orbitals because the 4s orbital is slightly lower in energy than the empty 3d orbitals (n+l rule). However, once electrons are in the 3d orbital, the 4s is no longer lower in energy, it becomes higher in energy than 3d so when ionisation occurs electrons are lost from the 4s orbital before they're lost from the 3d orbitals.Hence, the first electron is lost from 4s and the one after that, from 3d. So the new electronic configuration from Cu2+ is:1s2, 2s2, 2p6, 3s2, 3p6, 4s0, 3d9Therefore, option B is the correct answer.