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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
What are chemical twins? Write ‘two’ examples.
What are lanthanoids?
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?
Explain effects of lanthanoid contraction.
Which trivalent ion has the maximum size in the Lanthanoid series, i.e., Lanthanum ion (La3+) to Luteium ion (Lu3+)?
(at. no. of Lanthanum = 57 and Lutetium = 71)
What is the action of the following on lanthanoids?
a. water
b. Sulphur, heat
c. nitrogen, heat
The f-block elements are known as ____________.
Gadolinium belongs to 4f series. It’s atomic number is 64. Which of the following is the correct electronic configuration of gadolinium?
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)
Which of the following lanthanoids show +2 oxidation state besides the characteristic oxidation state +3 of lanthanoids?
(i) \[\ce{Ce}\]
(ii) \[\ce{Eu}\]
(iii) \[\ce{Yb}\]
(iv) \[\ce{Ho}\]
Although Zr belongs to 4d and Hf belongs to 5d transition series but it is quite difficult to separate them. Why?
Although +3 oxidation states is the characteristic oxidation state of lanthanoids but cerium shows +4 oxidation state also. Why?
On the basis of Lanthanoid contraction, explain the following:
Nature of bonding in \[\ce{La2O3}\] and \[\ce{Lu2O3}\] .
On the basis of Lanthanoid contraction, explain the following:
Trends in the stability of oxo salts of lanthanoids from \[\ce{La}\] to \[\ce{Lu}\].
In lanthanoid the last electron enters (n - 2)f subshell where n is equal to ______.
Mischmetal is an alloy consisting mainly of ______.
Cerium (Z = S8) is an important member of lanthanoids. Which of the following statements about cerium is incorrect?
Trivalent Lanthanoid ions such as La3+ (Z = 57) and Lu3+ (Z = 71) do not show any colour in their solution. Give a reason.
