Question

Explain: the compound of copper (II) are coloured but those of zinc are colourless.

Answer 1

Hola mate !! ✌️✌️

here's your answer ....⬇️⬇️
___________________________

▶️the compounds of copper (II) are coloured as it has one free electron its valence shell which absorbs radiation of visible region and gets excited to emit its complementary colour .

▶️whereas Zinc has no free electron . it has fully filled shells. Hence due to extra stable orbitals electron can't be excited by radiations of visible light. hence , its compounds are colourless .
_____________________________

$\large{hope\: it\: helps\: !!}$ ❤️❤️

Answer 2

The compound of copper (II) is colored but those of zinc are colorless because:

• The electronic configuration of Copper(II) is 3d⁹4s².
• It has 1 unpaired electron which is responsible for imparting colour.
• The electronic configuration of Zinc is 3d¹°4s².
• It has no unpaired electrons so it is colorless.
• Zinc has fulfilled a stable electronic configuration.
• The unpaired electron of Copper(II) absorbs the radiation of visible light which is responsible to impart color.

Hence, the compound of copper (II) is colored but those of zinc are colored.