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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 ion.
उत्तर
Factors responsible for colour of a transition metal ions:
- The presence of incompletely filled d – orbitals in metal ions.
- The presence of unpaired electrons in d – orbitals.
- d – d transition of electrons due to absorption of radiation in the visible region.
- Type of hybridisation in metal ion in the complex.
- Geometry of the complex containing transition metal ion.
संबंधित प्रश्न
Which metal in the first transition series (3d series) exhibits + 1 oxidation state most frequently and why?
Which of the following cations are coloured in aqueous solutions and why ?
Sc3+, V3+, Ti4+, Mn2+ (At. Nos. Sc = 21, V = 23, Ti = 22, Mn = 25)
The elements of 3d transition series are given as: Sc Ti V Cr Mn Fe Co
Answer the following: Write the element which shows maximum number of oxidation states. Give reason.
In 3d series (Sc to Zn), which element has the lowest enthalpy of atomisation and why?
|
`E_((M^(2+)/M)` |
Cr | Mn | Fe | Co | Ni | Cu |
| -0.91 | -1.18 | -0.44 | -0.28 | -0.25 | -0.34 |
From the given data of E0 values, answer the following questions :
(1) Why is `E_(((Cu^(2+))/(Cu)))` value exceptionally positive
(2) Why is `E_(((Mn^(2+))/(Mn)))` value is highly negative as compared to other elements
(3) Which is the stronger reducing agents Cr2+ or Fe2+ ? Give Reason.
Account for the following :
Zn is not considered as a transition element.
Describe the oxidising action of potassium dichromate and write the ionic equation for its reaction with iodide.
Write down the number of 3d electrons in the following ion:
Cu2+
Indicate how would you expect the five 3d orbitals to be occupied for this hydrated ions (octahedral).
Why do transition elements show variable oxidation states ? In 3d series (Sc to Zn), which elements shows the maximum number of oxidation state and why ?
How is potassium dichromate prepared from chrome iron ore?
Two metallic elements A and B have the following standard oxidation potentials: A = 0·40v B = - 0·80v. What would you expect if element A was added to an aqueous salt solution of element B? Give a reason for your answer.
Explain why:
(i) Mn2+ is more stable than Fe2+ towards oxidation to +3 state.
(At. no. of Mn = 25, Fe = 26)
(ii) Transition elements usually form coloured ions.
(iii) Zr and Hf exhibit similar properties.
(At. no. of Zr = 40, Hf = 72)
Which among the following transition metal has the lowest melting point?
The magnetic moment is associated with its spin angular momentum and orbital angular momentum. Spin only magnetic moment value of \[\ce{Cr^{3+}}\] ion is ______.
Why EΘ values for Mn, Ni and Zn are more negative than expected?
Transition elements show high melting points. Why?
Although fluorine is more electronegative than oxygen, but the ability of oxygen to stabilise higher oxidation states exceeds that of fluorine. Why?
Assertion: Separation of \[\ce{Zr}\] and \[\ce{Hf}\] is difficult.
Reason: Because \[\ce{Zr}\] and \[\ce{Hf}\] lie in the same group of the periodic table.
Answer the following question:
Which element of the first transition series has highest third ionisation enthalpy?
Identify the metal and justify your answer.
Carbonyl \[\ce{M(CO)5}\]
Account for the following:
In case of transition elements, ions of the same charge in a given series show progressive decrease in radius with increasing atomic number.
A metallic ion 'M' reacts with chloride ion to form white precipitate which is readily soluble in aqueous ammonia. Identify 'M'?
The standard electrode potentials of four elements A, B, C and D are – 3.05, – 1.66, – 0.40 and + 0.80. The highest chemical reactivity will be exhibited by
The product of oxidation of I– with \[\ce{MnO^{-}4}\] in alkaline medium is:-
The complex showing a spin-span magnetic moment of 2.82 B.M. is :-
On adding NaOH, solution to the aqueous solution of K2CrO7 the colour of the solution changes from
The value of Δ0 for \[\ce{RhCl^{3-}6}\] is 243 KJ/mol which wavelength of light will promote an electron from. The colour of the complex is ______.
Which of the following ions acts as a typical transition metal ion?
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:
Atomic sizes
