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प्रश्न
Write the factors which are related to the colour of transition metal ions.
Write the conditions of colour of transition metal ions.
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उत्तर
- Metal ions exhibit the presence of incompletely filled d-orbitals.
- The presence of unpaired electrons in d-orbitals.
- The d-d transition of electrons due to absorption of radiation in the visible region.
- The metal ion in the complex undergoes a type of hybridisation.
- The geometry of the complex containing transition metal ions is described.
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संबंधित प्रश्न
Why is Sc3+ colourless while Ti3+ coloured? (Atomic number Sc = 21, Ti =22)
The elements of 3d transition series are given as: Sc Ti V Cr Mn Fe Co
Answer the following: Which element is a strong oxidising agent in +3 oxidation state and why?
In 3d series (Sc to Zn), which element has the lowest enthalpy of atomisation and why?
Account for the following:
Zn is not considered as a transition element.
Explain briefly how +2 state becomes more and more stable in the first half of the first row transition elements with increasing atomic number?
How is the variability in oxidation states of transition metals different from that of the non-transition metals? Illustrate with examples.
Which metal in the first series of transition metals exhibits +1 oxidation state most frequently and why?
Write balanced chemical equations for the conversion of `CrO_4^(2-)` to `Cr_2O_7^(2-)` in acidic medium and `Cr_2O_7^(2-)` to `CrO_4^(2-)`
in basic medium.
Give reasons: Sc3+ is colourless in aqueous solution whereas Ti3+ is coloured.
Explain why transition metals and their compounds act as a catalyst.
Give reasons for the following:
The transition metals generally form coloured compounds.
Metallic radii of some transition elements are given below. Which of these elements will have highest density?
| Element | \[\ce{Fe}\] | \[\ce{Co}\] | \[\ce{Ni}\] | \[\ce{Cu}\] |
| Metallic radii/pm | 126 | 125 | 125 | 128 |
When acidified \[\ce{K2Cr2O7}\] solution is added to \[\ce{Sn^{2+}}\] salts then \[\ce{Sn^{2+}}\] changes to ______.
Why does copper not replace hydrogen from acids?
While filling up of electrons in the atomic orbitals, the 4s orbital is filled before the 3d orbital but reverse happens during the ionisation of the atom. Explain why?
Match the catalysts given in Column I with the processes given in Column II.
| Column I (Catalyst) | Column II (Process) |
| (i) \[\ce{Ni}\] in the presence of hydrogen | (a) Zieglar Natta catalyst |
| (ii) \[\ce{Cu2C12}\] | (b) Contact process |
| (iii) \[\ce{V2O5}\] | (c) Vegetable oil to ghee |
| (iv) Finely divided iron | (d) Sandmeyer reaction |
| (v) \[\ce{TiCl4 + Al (CH3)3}\] | (e) Haber's Process |
| (f) Decomposition of KCIO3 |
When a chromite ore (A) is fused with sodium carbonate in free excess of air and the product is dissolved in water, a yellow solution of compound (B) is obtained. After treatment of this yellow solution with sulphuric acid, compound (C) can be crystallised from the solution. When compound (C) is treated with KCl, orange crystals of compound (D) crystallise out. Identify A to D and also explain the reactions.
Answer the following question:
Which element of the first transition series has highest second ionisation enthalpy?
Identify the metal and justify your answer.
\[\ce{MO3F}\]
The orientation of an atomic orbital is governed by
Catalytic hydrogenation of benzene gives
The product of oxidation of I– with \[\ce{MnO^{-}4}\] in alkaline medium is:-
Why is the `"E"_(("V"^(3+)//"V"^(2+)))^"o"` value for vanadium comparatively low?
Which one among the following metals of the 3d series has the lowest melting point?
Which of the following transition metals shows +1 and +2 oxidation states?
Which property of transition metals enables them to behave as catalysts?
Consider the following standard electrode potential values:
\[\ce{Fe^{3+}_{ (aq)} + e^- -> Fe^{2+}_{ (aq)}}\], E0 = +0.77 V
\[\ce{MnO^{-4}_{ (aq)} + 8H^+ + 5e^- -> Mn^{2+}_{ (aq)} + 4H2O_{(l)}}\], E0 = +1.51 V
What is the cell potential for the redox reaction?
Give a reason for the following.
Some transition metals and their compounds get attracted towards the magnetic field.
Compare the general characteristics of the first series of the transition metals with those of the second and third series metals in the respective vertical columns. Give special emphasis on the following point:
Oxidation states
The E° value for the Mn2+/Mn2+ couple is more positive than that of Cr3+/Cr2+ or Fe3+/Fe2+ due to the change of:
