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प्रश्न
Compare the chemistry of actinoids with that of the lanthanoids with special reference to oxidation state.
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उत्तर
Lanthanoids show limited oxidation states (+2, +3, +4), in which the +3 oxidation state is the most common. This is because of the large energy gap between the 4f, 5d, and 6s subshells. On the other hand, actinoids show a large number of oxidation states because the energy gap between 5f, 6d, and 7s subshells is smaller.
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संबंधित प्रश्न
What are chemical twins? Write ‘two’ examples.
Which among the following pairs of elements is 'not' an example of chemical twins?
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.
Explain effects of lanthanoid contraction.
The f-block elements are known as ____________.
Although +3 oxidation states is the characteristic oxidation state of lanthanoids but cerium shows +4 oxidation state also. Why?
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.
On the basis of Lanthanoid contraction, explain the following:
Radii of 4d and 5d block elements.
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?
In lanthanoid the last electron enters (n - 2)f subshell where n is equal to ______.
Zr (Z = 40) and Hf (Z = 72) have similar atomic and ionic radii because of ______.
Write any two consequences of Lanthanoid Contraction.
Cerium (Z = S8) is an important member of lanthanoids. Which of the following statements about cerium is incorrect?
Write a note on lanthanoids.
State a reason for the following:
La(OH)3 is more basic than Lu(OH)3.
Trivalent Lanthanoid ions such as La3+ (Z = 57) and Lu3+ (Z = 71) do not show any colour in their solution. Give a reason.
Name an important alloy which contains some of the lanthanoid metals. Mention its uses.
