TS EAMCET 11-Sep-2020 Shift 2 Solved Paper

La3+(Z=57) has 54 electrons.
Ti3+(Z=22) has 19 electrons.
Lu3+(Z=71) has 68 electrons.
and Sc3+(Z=21) has 18 electrons.
The species with unpaired electrons show colour in aqueous solution.
Because,
Ti3+=[Ar]⋅4s1
Thus, has one unpaired electron.