Advertisements
Advertisements
प्रश्न
In the series Sc (Z = 21) to Zn (Z = 30), the enthalpy of atomization of zinc is the lowest, i.e., 126 kJ mol−1. Why?
उत्तर
The electrons of the 3d orbitals of zinc are not used in bonding, whereas the electrons of the d orbitals of all the remaining metals of the 3d series are used in forming bonds. Hence the value of the atomization enthalpy of zinc is the lowest in the series.
APPEARS IN
संबंधित प्रश्न
Which is a stronger reducing agent, Cr2+ or Fe2+ and why?
Predict which of the following will be coloured in the aqueous solution?
Ti3+, V3+, Cu+, Sc3+, Mn2+, Fe3+ and Co2+. Give reasons for each.
Compare the stability of +2 oxidation state for the elements of the first transition series.
Use Hund’s rule to derive the electronic configuration of Ce3+ ion and calculate its magnetic moment on the basis of ‘spin-only’ formula.
How would you account for the following?
Transition metals and their compounds act as catalysts.
Explain why transition elements form alloys.
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)
Transition elements show high melting points. Why?
Out of \[\ce{Cu2Cl2}\] and \[\ce{CuCl2}\], which is more stable and why?
Reactivity of transition elements decreases almost regularly from Sc to Cu. Explain.
Match the properties given in Column I with the metals given in Column II.
| Column I (Property) | Column II (Metal) | |
| (i) | An element which can show +8 oxidation state | (a) \[\ce{Mn}\] |
| (ii) | 3d block element that can show | (b) \[\ce{Cr}\] |
| upto +7 oxidation state | (c) \[\ce{Os}\] | |
| (iii) | 3d block element with highest melting point | (d) \[\ce{Fe}\] |
Assertion: The highest oxidation state of osmium is +8.
Reason: Osmium is a 5d-block element.
Catalytic hydrogenation of benzene gives
The spin magnetic moment of cobalt in the compound Hg [Co(SCN)4] is:-
Which one of the following characters tie of the transition metal is associated with higher catalytic activity?
On adding NaOH, solution to the aqueous solution of K2CrO7 the colour of the solution changes from
Which of the following ions has the maximum magnetic moment?
Which of the following ions acts as a typical transition metal ion?
Complete the following reaction and justify that it is a disproportionation reaction:
\[\ce{3MnO^{2-}4 + 4H^+ -> \underline{}\underline{}\underline{}\underline{} + \underline{}\underline{}\underline{}\underline{} + 2H2O}\]
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
