Question

Lanthanum and lutetium do not show colouration in solution. Why?

Answer 1

Lanthanum(La 3+) have 4f ^0 and lutetium (Lu 3+) have 4f^14 configuration. Because of the absence of an unpaired electrons , these ions impart no colour to the solution.

Answer 2

Answer:

None of them have vacant d orbital for d-d transition, so no colour is expressed.

Explanation: