question_answer

\[C{{u}^{+}}\] is a \[{{d}^{10}}\] ion and colourless whereas \[C{{u}_{2}}O\] is red and \[C{{u}_{2}}S\] is black. Explain.

Answer:

                  In \[C{{u}^{+}}\] ion \[({{d}^{10}}),\] there is no\[d-{{d}^{*}}\]transition and the ion is colourless. Both \[C{{u}_{2}}O\] and \[C{{u}_{2}}S\] are coloured because of charge transfer of electrons from \[{{O}^{2-}}\] or \[{{S}^{2-}}\] to the vacant orbital of \[C{{u}^{+}}\] ion.