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Ionisation enthalpies of Ce, Pr and Nd a...

Ionisation enthalpies of `Ce, Pr` and `Nd` are higher than those of `Th, Pa` and `U`. Why ?

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The first three element belong to lanthanoids (`4f-`obitals are filled) while the last three elements are actinoids (`5f-`orbital are filled). We all know that `5f-`orbitals have less penetration in the inner core as compared to `4f-`orbitals. As a result, ionisation enthalpies of lanthanoids are expected to be more than those of actinoids.
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DINESH PUBLICATION-D-AND -F BLOCK ELEMENTS-Short Answer type questions.
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  2. Why E^(@) value of Mn, Ni and Zn are more negative than expected ?

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  3. Why is first ionisation enthalpy of Cr lower than that of Zn ?

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  4. Transition elements show high melting points. Why?

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  5. Out of Cu(2)Cl(2), which is more stable and why ?

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  6. When a brown compound of manganese [A] is treated with HCl, it gives a...

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  7. When Cu^(2+) ion is treated with KI, a white precipitate is formed. Ex...

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  8. Although flurorine is more electronegative than oxygen, but the abilit...

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  9. Although Cr^(3+) and Co^(2+) ions have same number of unpaired electro...

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  10. Ionisation enthalpies of Ce, Pr and Nd are higher than those of Th, Pa...

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  11. Although Zr belongs to 4d and Hf belongs to 5d transition series, but...

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  12. Although +3 oxidation stae is thje characteristic oxidation state of ...

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  13. Explain why does colour of KMnO(4) disappear when oxalic acids is adde...

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  14. When orange solution containing Cr(2)O(7)^(2-) ion is treated with an ...

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  15. A solution of KMnO(4) on reduction yields either a colourless solution...

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  16. The second and third rows of transition elements resemble each other ...

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  17. E^(@) of Cu is +0.34 V while that of Zn is -0.736 V. Explain.

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  18. The halides of transition elements become more covalent with increasin...

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  19. While filling up electron in the atomic orbitals, 4s orbital is filled...

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