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The gradual decrease in size (actionoid ...

The gradual decrease in size (actionoid contraction) is from element to element is greater among the actinoids than that among the lanthanoids (lanthanoid contraction).

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Actinoid contraction is greater than lanthanoid contraction. This is due to the poor shielding by 5f-electrons than by 4f electrons.
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Give an explanation for each of the following observations: (i) The gradual decrease in size (actinoid con-traction) from element to element is greater among the actinoids than that among the lanthanoids (lanthanoid contraction). (ii) The greater number of oxidation states are exhibited by the members in the middle of a transition series. (iii) With the same d-orbital (d^4) , Cr^(2+) ion is a reducing agent but Mn^(3+) ion is an oxidising agent.

(a) Complete the following chemical equations for reactions : (i) MnO_(4(aq))^(-) + S_(2)O_(3(aq))^(2-) + H_(2)O_((l)) to (ii) Cr_(2)O_(7 (aq))^(2-) + H_(2)S_((g)) + H_((aq))^(+) to (b) Give an explanation for each of the following observations : (i) The gradual decrease in size (actinoid contraction) from element to element is greater among the actinoids than that among the lanthanoids (lanthanoid contraction.) (ii) The greatest number of oxidation states are exhibited by the members in the middle of a transition series. (iii) With the same d-orbitals configuration (d^(4)) Cr^(2+) ion is a reducing agent but Mn^(3+) ion is an oxidising agent .

Reason of lanthanoid contraction is

Actinoid contraction is greater from element to element than lanthanoid contraction Why?

Why actinoid contraction is more than lanthanoid contraction

What is meant by 'lanthanoid contraction'?

Lanthanoid contraction is caused due to:

Lanthanoid contraction is due to increase in

What is lanthanoid contraction? What are the consequences of lanthanoid contraction?

What is lanthanoid contraction? What are the consequences of lanthanold contraction?

ICSE-d- AND- f- BLOCK ELEMENTS-EXERCISE (PART-II) (DESCRIPTIVE QUESTIONS)(VERY SHORT ANSWER QUESTIONS)
  1. Which is more basic La(OH)(3)zor Lu(OH)3 ? Why?

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  2. What is the basic difference between the electronic configurations of ...

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  3. Why do transition elements show similarities along the horizontal peri...

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  4. Why the third ionization energy of manganese (atomic number 25) unexpe...

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  5. Which property of the transition elements makes them good catalysts?

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  6. What are coinage metals ?

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  7. Write the ionic reaction for the reaction between MnO4^(-) ions and ox...

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  8. Write one reaction using alkaline KmnO4.

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  9. Write the electronic configuration of the element with atomic number 1...

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  10. What is the electronic cofiguration of charomium atom (z= 24) Give re...

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  11. Why are Cd^(2+) salts white ?

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  12. Though a transition element, scandium (Z = 21) does not exhibit variab...

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  13. Account for the following: There are irregularities in the electron...

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  14. The gradual decrease in size (actionoid contraction) is from element t...

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  15. (a) Complete the following chemical equations : (i) MnO(4)^(-) (aq) ...

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  16. Assign reasons for the following : (i) Copper (I) ion is not known i...

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  17. Why is Cr^(2+) reducing and Mn^(3+) oxidising when both have d^(4) con...

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  18. How would you accont for the following? Lanthanoids form primarily +...

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  19. How would you account for the following : (i) Among lanthanoids , Ln...

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  20. Explain the following observations : (i) Many of the transition elem...

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