Transistion Metal Ions Question?

Question

Given that the electronic configuration of silver is: [Kr] 4d10 5s1
Deduce the colour of [AgCl2]-
Explain your answer.

I have absolutely no idea how to attempt to answer this, what are the steps in doing so? Thanks

Answer 1

When silver ionizes to Ag+, the electron that is lost is the 5s1 electron (while it may be filled first, it is technically lost first as it is furthest from the nucleuis).

The electron configuration of Ag+ is then [Kr] 4d10.

Color in transition metals arises from d->d orbital transitions, whose energy corresponds to wavelengths of visible light. For silver, there are no possible d->d transitions, as all five d orbitals are filled. As a result, there is no electronic transition for silver that is in the visible region, so a solution of [AgCl2]- would be colorless.