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प्रश्न
How would you account for the following:
There is a greater range of oxidation states among the actinoids than among the lanthanides.
Account for the following:
Actinoids show more number of oxidation states than lanthanoids.
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उत्तर
Actinides exhibit larger oxidation states than lanthanides because of the very small energy gap between 5f, 6d, and 7s subshells as compared to 4f, 5d, and 6s orbitals in the case of lanthanoids. Thus, the outermost electrons get easily excited to the higher energy levels, giving variable oxidation states.
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संबंधित प्रश्न
Compare the chemistry of actinoids with that of the lanthanoids with special reference to chemical reactivity.
Explain the cause of Lanthanoids contraction.
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 oxidation states is the characteristic oxidation state of lanthanoids but cerium shows +4 oxidation state also. Why?
Match the compounds/elements given in Column I with uses given in Column II.
| Column I (Compound/element) | Column II (Use) | |
| (i) | Lanthanoid oxide | (a) Production of iron alloy |
| (ii) | Lanthanoid | (b) Television screen |
| (iii) | Misch metal | (c) Petroleum cracking |
| (iv) | Magnesium based alloy is constituent of | (d) Lanthanoid metal + iron |
| (v) | Mixed oxides of lanthanoids are employed | (e) Bullets |
| (f) In X-ray screen |
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:
Stability of the complexes of lanthanoids.
Which one of the lanthanoids given below is the most stable in divalent form?
Cerium (Z = S8) is an important member of lanthanoids. Which of the following statements about cerium is incorrect?
The pair of lanthanoid ions which are diamagnetic is:
