Which of the `Ni^(2+)`, `Ti^(3+)` and `Cu^(2+)` are expected to be coloured and why ?

Which of the Zn^(2+) , Sc^(3+) and Co^(2+) are expected to be coloured and why ?

Which of the Zn^(2+) , Fe^(3+) and Mn^(2+) are expected to be coloured and why ?

Out of Cu^(2+) and Cu^(+) ion, which one is colourless and why?

Which of the Co^(2+) , Fe^(2+) , Sc^(3+) are coloured and why ?

Which of the following ions are expected to be coloured ? Ni^(2+), Ti^(3+), Cu^(+), Sc^(3+), Zn^(2+)

Out of the ions Ni^(2+) , Zn^(2+) and Cu^2+) , which will give coloured aqueous solution and what will be the magnetic beghaviour of each ion ? (Atomic number of Ni = 28, Zn =30 and Cu = 29).

Which of the two : O_2NCH_2CH_2O^(-) " or " CH_3CH_2O^(-) is expected to be more stable and why?

Ions of Zn^(2+) and Ti^(4+) are colourless while Cu^(2+) and Ni^(2+) are coloured . Why ?

Out of Co^(2+) , Zn^(2+) and Cu^+(2+) which will give aqueous coloured solution ?