NEET-XII-Chemistry
08: The d-and f-Block Elements
- #18Predict which of the following will be coloured in aqueous solution? Ti3+, V3+,
Cu+, Sc3+, Mn2+, Fe3+ and Co2+. Give reasons for each.
Ans : Only the ions that have electrons in d-orbital and in which d-d transition is possible will be coloured. The ions in which d-orbitals are empty or completely filled will be colourless as no d-d transition is possible in those configurations.
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Element
Atomic Number
Ionic State
Electronic configuration in ionic state
Ti
22
T13+
[Ar] 3d1
V
23
V3+
[Ar] 3d2
Cu
29
Cu+
[Ar] 3d10
Sc
21
Sc3+
[Ar]
Mn
25
Mn2+
[Ar] 3d5
Fe
26
Fe3+
[Ar] 3d5
Co
27
Co2+
[Ar] 3d7
From the above table, it can be easily observed that only Sc3+ has an empty d-orbital and Cu+ has completely filled d-orbitals. All other ions, except Sc3+ and Cu+, will be coloured in aqueous solution because of d-d transitions.
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