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प्रश्न
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:
Ionisation enthalpies
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उत्तर
- In every series, the first ionization enthalpy generally increases gradually as we move from left to right, although some exceptions are observed in every series.
- In the same horizontal group, the first ionization enthalpy of some elements of 4d series is higher and that of some elements is lower as compared to the elements of 3d series, although the first ionization enthalpy of 5d series is higher as compared to 3d and 4d series.
- The reason for this is the weak shielding effect of the nucleus on the 4f electrons in the 5d series.
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संबंधित प्रश्न
Explain why is Fe3+ more stable than Fe2+?
Why do the transition elements have higher enthalpies of atomisation?
To what extent do the electronic configurations decide the stability of oxidation states in the first series of the transition elements? Illustrate your answer with examples.
Which metal in the first series of transition metals exhibits +1 oxidation state most frequently and why?
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).
NF3 is possible, but NF5 is not. Why?
How would you account for the following?
Transition metals and their compounds act as catalysts.
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 ?
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) \[\ce{Ni}\]
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.
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.
Sodium this sulphate is used in photography because of its:-
Which of the following species has maximum magnetic momentum?
Among the following pairs of ions, the lower oxidation state in aqueous solution is more stable than the other in:-
On adding NaOH, solution to the aqueous solution of K2CrO7 the colour of the solution changes from
The oxidation state of Fe in [Fe(CO)5] is ______.
Assertion (A): Transition metals show their highest oxidation state with oxygen.
Reason (R): The ability of oxygen to form multiple bonds to metals.
The second ionization enthalpies of chromium and manganese are 1592 and 1509 kJ/mol respectively. Explain the lower value of Mn.
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
