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प्रश्न
The chemistry of the actinoid elements is not so smooth as that of the Lanthanoids. Justify this statement by giving some examples from the oxidation state of these elements.
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उत्तर
The oxidation states of lanthanoids are +2, +3, and +4. Of these, +3 is the most common state. The limited number of oxidation states is due to the large energy difference between the 4f, 5d, and 6s sub-orbitals. In contrast, actinoids show many oxidation states, such as +2, +3, +4, +5, +6, and +7, although their most common state is +3. This is because there is a small energy difference between the 5f, 6d, and 7s sub-orbitals.
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संबंधित प्रश्न
Account for the following :
Zr and Hf have almost similar atomic radii.
Name a member of the lanthanoid series which is well known to exhibit +4 oxidation state.
What are the different oxidation states exhibited by the lanthanoids?
Write the electronic configurations of the element with the atomic number 61.
Explain the cause of Lanthanoids contraction.
What is lanthanoid contraction? Write the.............
Gadolinium belongs to 4f series. It’s atomic number is 64. Which of the following is the correct electronic configuration of gadolinium?
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:
Trends in the stability of oxo salts of lanthanoids from \[\ce{La}\] to \[\ce{Lu}\].
On the basis of Lanthanoid contraction, explain the following:
Trends in acidic character of lanthanoid oxides.
Which of the following pairs has the same ionic size?
The lathanide ion that would show colour is ______.
Cerium (Z = S8) is an important member of lanthanoids. Which of the following statements about cerium is incorrect?
Write a note on lanthanoids.
Why is Mn2+ ion more stable than Fe2+ ion?
(Atomic numbers of Mn = 25 and Fe = 26)
Assertion: There is a continuous increase in size among Lanthanoids with an increase in atomic number.
Reason: Lanthanoids do not show Lanthanoid contraction.
Name an important alloy which contains some of the lanthanoid metals.
