Question

Which is not correct statement ?

• A. Ions of d-block elements are coloured due to d-d transition.
• B. Ions of f-block elements are coloured due to f-f tsransition.
• C. $\left[Sc\right(H_{2}O{)}_6{]}^{3+},\left[Ti\right(H_{2}O{)}_6{]}^{4+}$ are coloured complexes.
• D. $C{u}^{+}$ is colourless ion.

Answer 1

The correct option is C $\left[Sc\right(H_{2}O{)}_6{]}^{3+},\left[Ti\right(H_{2}O{)}_6{]}^{4+}$ are coloured complexes.

A. Ions of d-block elements contain unpaired d electrons. They are coloured due to d-d transition. Thus, the option A is correct.
B. Ions of f-block elements contain unpaired f electrons. They are coloured due to f-f transition. Thus, the option B is correct.
C. $\left[Sc\right(H_{2}O{)}_6{]}^{3+},\left[Ti\right(H_{2}O{)}_6{]}^{4+}$ are colourless compounds due to $3d^0$ outer electronic configuration. No unpaired electron is present. Thus, the option C is incorrect.
D. $C{u}^{+}$ ion has $3d^{10}$ electronic configuration in which all the electrons are paired. Hence, it is colourless. Thus, the option D is correct.