Question

Transition metals are generally paramagnetic and coloured due to the presence of unpaired electrons. But in some such cases also have been seen that there is no unpaired electrons in the central atom, i.e. no $d-d$ transition appears, e.g. $KMnO _{4}$ and they have intense colour. In such case charge transfer plays a key role in imparting colour to the substance.
Which of the following statements is not correct?

• A. $d$-block metal ions are usually coloured
• B. $d-d$ transition is responsible for the colour of elements of $d$-block
• C. All the complexes of $Cu ^{1+}$ are colourless because of the presence of $d^{1}$ configuration
• D. $Cu ^{2+}$ is charge transfer between metal and legal

Answer 1

Answer: (C)

Complexes of $Cu ^{+}$are coloured due to charge tranfer.