question_answer 117)

  The electronic configuration of valence shell of \[Cu\] is \[3{{d}^{10}},4{{s}^{1}}\] and not \[3{{d}^{9}},4{{s}^{2}}\]. How is this configuration explained?

Answer:

                 Configuration of \[C{{u}_{29}}=3{{d}^{10}},4{{s}^{1}}\] This, configuration is correct because it has extra stability of fully filled d-subshell.