JEE Main202229 Jul 2022Morning ShiftChemistryd and f Block ElementsActual
In following pairs, the one in which both transition metal ions are colourless is
Options
- ASc 3 + , Zn 2 +
- BTi 4 + , Cu 2 +
- CV 2 + , Ti 3 +
- DZn 2 + , Mn 2 +
Correct answer
A. Sc 3 + , Zn 2 +
Step-by-step solution
d -block elements form coloured ions due to presence of unpaired electrons in them. since there are no unpaired electrons in Sc 3 + and Zn 2 + ions, they are colourless. No of unpaired e - Ti 3 + - [ Ar ] 3   d 1 , Cu 2 + - [ Ar ] 3   d 9 Sc 3 + - [ Ar ] 3   d 0 , Zn 2 + - [ Ar ] 3   d 10   T i 4 + - [ Ar ] 3   d 0         V 2 + - [ Ar ] 3   d 3   , No d-d transitions in ions with d 0 & d 10 configuration. Therefore they are colourless.