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कर्नाटक बोर्ड पी.यू.सी.पीयूसी विज्ञान 2nd PUC Class 12

On the basis of Lanthanoid contraction, explain the following: Nature of bonding in LaX2OX3 and LuX2OX3 .

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प्रश्न

On the basis of Lanthanoid contraction, explain the following:

Nature of bonding in \[\ce{La2O3}\] and \[\ce{Lu2O3}\] .

दीर्घउत्तर
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उत्तर

As per fajan’s rule, smaller the size of ion, greater is its tendency to make covalent bonds as the positively charged cation strongly attract the negatively charged electron cloud.

On moving from \[\ce{La}\] to \[\ce{Lu}\] in the lanthanoid series, the atomic size decreases so the covalent character increases. Hence, \[\ce{La2O3}\] is ionic and \[\ce{Lu2O3}\] is covalent.

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पाठ 8: The d-and f-Block Elements - Multiple Choice Questions (Type - I) [पृष्ठ ११५]

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एनसीईआरटी एक्झांप्लर Chemistry Exemplar [English] Class 12
पाठ 8 The d-and f-Block Elements
Multiple Choice Questions (Type - I) | Q 67.(i) | पृष्ठ ११५

संबंधित प्रश्‍न

What are chemical twins? Write ‘two’ examples.


Which among the following pairs of elements is 'not' an example of chemical twins?


Compare the chemistry of actinoids with that of lanthanoids with special reference to electronic configuration.


Compare the chemistry of actinoids with that of the lanthanoids with special reference to atomic and ionic sizes.


Compare the chemistry of actinoids with that of the lanthanoids with special reference to chemical reactivity.


Write the electronic configuration of the element with the atomic number 61.


Write the different oxidation states of iron


Explain effects of lanthanoid contraction.


Which trivalent ion has the maximum size in the Lanthanoid series, i.e., Lanthanum ion (La3+) to Luteium ion (Lu3+)? 

(at. no. of Lanthanum  = 57 and Lutetium = 71)


General electronic configuration of actinoids is `(n-2)f^(1-14)(n - 1)d^(0-2)ns^2`.Which of the following actinoids have one electron in 6d orbital?

(i) U (Atomic no. 92)

(ii) Np (Atomic no.93)

(iii) Pu (Atomic no. 94)

(iv) Am (Atomic no. 95)


Although +3 is the characteristic oxidation state for lanthanoids but cerium also shows +4 oxidation state because:

(i) it has variable ionisation enthalpy

(ii) it has a tendency to attain noble gas configuration

(iii) it has a tendency to attain f 0 configuration

(iv) it resembles Pb4+ 


Match the statements given in Column I with the oxidation states given in Column II.

  Column I Column II
(i) Oxidation state of Mn in MnO2 is (a) + 2
(ii) Most stable oxidation state of Mn is (b) + 3
(iii) Most stable oxidation state of  (c) + 4
  Mn in oxides is (d) + 5
(iv) Characteristic oxidation state of lanthanoids is (e) + 7

On the basis of Lanthanoid contraction, explain the following:

Trends in the stability of oxo salts of lanthanoids from \[\ce{La}\] to \[\ce{Lu}\].


On the basis of Lanthanoid contraction, explain the following:

Radii of 4d and 5d block elements.


How would you account for the following:

There is a greater range of oxidation states among the actinoids than among the lanthanides.


The titanium (Z = 22) compound that does not exist is:-


Zr (Z = 40) and Hf (Z = 72) have similar atomic and ionic radii because of ______.


Mischmetal is an alloy consisting mainly of ______.


Write a note on lanthanoids.


Assertion: There is a continuous increase in size among Lanthanoids with an increase in atomic number.

Reason: Lanthanoids do not show Lanthanoid contraction.


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