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प्रश्न
Mention the type of compounds formed when small atoms like H, C and N get trapped inside the crystal lattice of transition metals. Also give physical and chemical characteristics of these compounds.
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उत्तर
Compounds formed when small atoms like H, C and N get trapped inside the crystal lattice of transition metals are called interstitial compounds.
Properties of such compounds are:
(i) High melting points higher than those of pure metals.
(ii) These compounds are very hard.
(iii) They retain metallic conductivity.
(iv) They are chemically inert.
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संबंधित प्रश्न
In 3d series (Sc to Zn), which element has the lowest enthalpy of atomisation and why?
What are inner transition elements?
Give reasons Iron has the higher enthalpy of atomization than that of copper.
The paramagnetic character in the 3d-transition series elements increases up to Mn and then decreases.
Which among the following transition metal has the lowest melting point?
Maximum oxidation state is shown by ____________.
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) \[\ce{Ni}\]
Although \[\ce{Cr^3+}\] and \[\ce{Co^2+}\] ions have same number of unpaired electrons but the magnetic moment of \[\ce{Cr^3+}\] is 3.87 B.M. and that of \[\ce{Co^2+}\] is 4.87 B.M. Why?
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?
The element with atomic number 53 belongs to
The element with atomic number 46 belongs to
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
Give reasons for the following statement:
Zn, Cd, and Hg are soft metals.
The oxidation state of Fe in [Fe(CO)5] is ______.
Account for the following:
Sc3+ is colourless whereas Ti3+ is coloured in an aqueous solution.
Assertion (A): Transition metals have high enthalpy of atomisation.
Reason (R): Greater number of unpaired electrons in transition metals results in weak metallic bonding.
Which of the following transition metals shows +1 and +2 oxidation states?
Complete the following reaction and justify that it is a disproportionation reaction:
\[\ce{3MnO^{2-}4 + 4H^+ -> \underline{}\underline{}\underline{}\underline{} + \underline{}\underline{}\underline{}\underline{} + 2H2O}\]
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 ease with which iron can be oxidised as compared to a similar process for either chromium or manganese metal.
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
