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प्रश्न
Answer the following question:
Which element of the first transition series has lowest enthalpy of atomisation?
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उत्तर
Zinc is the element of the first transition series that has the lowest enthalpy of atomisation. The electronic configuration of zinc is: \[\ce{3d^10 4s^2}\]. This is because it has filled 3d-subshell and filled 4s-subshell so no unpaid electron is available for metallic bonding.
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संबंधित प्रश्न
Account for the following:
Cr2+ is a strong reducing agent.
Account for the following:
Cu+ ion is unstable in aqueous solution.
Which of the d-block elements may not be regarded as the transition elements?
For M2+/M and M3+/M2+ systems, the EΘ values for some metals are as follows:
| Cr2+/Cr | −0.9 V |
| Mn2+/Mn | −1.2 V |
| Fe2+/Fe | −0.4 V |
| Cr3/Cr2+ | −0.4 V |
| Mn3+/Mn2+ | +1.5 V |
| Fe3+/Fe2+ | +0.8 V |
Use this data to comment upon:
The stability of Fe3+ in acid solution as compared to that of Cr3+ or Mn3+.
How would you account for the following:
Cobalt (II) is stable in aqueous solutions, but in the presence of complexing reagents, it is easily oxidised.
Write the factors which are related to the colour of transition metal ions.
Complete and balance the following chemical equations
`MnO_4^(-) + H_2O + I^(-) ->`
Give reasons: Sc3+ is colourless in aqueous solution whereas Ti3+ is coloured.
Dissociation of H2S is suppressed in acidic medium.
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.
Transition elements form binary compounds with halogens. Which of the following elements will form \[\ce{MF3}\] type compounds?
(i) \[\ce{Cr}\]
(ii) \[\ce{Co}\]
(iii) \[\ce{Cu}\]
(iv) \[\ce{Ni}\]
Why does copper not replace hydrogen from acids?
Identify the metal and justify your answer.
Carbonyl \[\ce{M(CO)5}\]
On the basis of the figure given below, answer the following questions:
- Why Manganese has lower melting point than Chromium?
- Why do transition metals of 3d series have lower melting points as compared to 4d series?
- In the third transition series, identify and name the metal with the highest melting point.
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 spin magnetic moment of cobalt in the compound Hg [Co(SCN)4] is:-
Which does not belong to first transition series?
The product of oxidation of I– with \[\ce{MnO^{-}4}\] in alkaline medium is:-
Among the following pairs of ions, the lower oxidation state in aqueous solution is more stable than the other in:-
Account for the following:
Sc3+ is colourless whereas Ti3+ is coloured in an aqueous solution.
