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

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

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प्रश्न

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

दीर्घउत्तर
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उत्तर

Both lanthanoids and actinoids show a progressive decrease in the size of their atoms and ions (M3+) across the series. In lanthanoids, this decrease is called lanthanoid contraction, while in actinoids, it is called actinoid contraction.
However, the decrease in size between two successive elements is higher in actinoids than in lanthanoids (i.e., actinoid contraction is more pronounced than lanthanoid contraction). This is because 5f electrons provide a poorer screening/shielding effect than 4f electrons, causing the outer electrons in actinoids to experience a stronger effective nuclear charge.
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अध्याय 4: d-and ƒ-Block Elements - REVIEW EXERCISES [पृष्ठ ४९२]

APPEARS IN

नूतन Chemistry [English] Class 12 ISC
अध्याय 4 d-and ƒ-Block Elements
REVIEW EXERCISES | Q 8.58 (i) | पृष्ठ ४९२
नूतन Chemistry [English] Class 12 ISC
अध्याय 4 d-and ƒ-Block Elements
'NCERT TEXT-BOOK, Exercises | Q 8.20 (ii) | पृष्ठ ५०७
एनसीईआरटी Chemistry Part 1 and 2 [English] Class 12
अध्याय 4 The d-block and f-block Elements
Exercises | Q 4.20 (ii) | पृष्ठ ११६

संबंधित प्रश्न

Define lanthanoid contraction.


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.


Explain, why lanthanum (Z = 57) forms La3+ ion, while cerium (Z = 58) forms Ce4+ ion?


Account for the following: 

Zn, Cd and Hg are soft metals.


Explain the cause of Lanthanoids contraction.


What is the action of the following on lanthanoids?
a. water
b. Sulphur, heat
c. nitrogen, heat


What is lanthanoid contraction?


The f-block elements are known as ____________.


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+ 


Although +3 oxidation states is the characteristic oxidation state of lanthanoids but cerium shows +4 oxidation state also. Why?


Match the property given in Column I with the element given in Column II.

  Column I (Property) Column II (Element)
(i) Lanthanoid which shows
+4 oxidation state
(a) Pm
(ii) Lanthanoid which can show +2
oxidation state
(b) Ce
(iii) Radioactive lanthanoid (c) Lu
(iv) Lanthanoid which has 4f7
electronic configuration in +3
oxidation state
(d) Eu
(v) Lanthanoid which has 4f14
electronic configuration in
+3 oxidation state
(e) Gd
    (f) Dy

The lathanide ion that would show colour is ______.


Write a note on lanthanoids.


State a reason for the following:

La(OH)3 is more basic than Lu(OH)3.


Name an important alloy which contains some of the lanthanoid metals.


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