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प्रश्न
Although +3 is the characteristic oxidation state for lanthanoids but cerium also shows +4 oxidation state because:
(i) it has variable ionisation enthalpy
(ii) it has a tendency to attain noble gas configuration
(iii) it has a tendency to attain f 0 configuration
(iv) it resembles Pb4+
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उत्तर
(ii) it has a tendency to attain noble gas configuration
(iii) it has a tendency to attain f 0 configuration
Explanation:
Electronic configuration of cerium:
\[\ce{Ce - 4f^1 5d^1 6s^2}\]
\[\ce{Ce^4+ − 4f^0 5d^0 6s^0}\]
Lead has the tendency to lose its four outer electrons to attain Noble gas configuration and this removal of electrons corresponds to the f∘ configuration and cause it to be stable in +4 oxidation state.
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संबंधित प्रश्न
What are chemical twins? Write ‘two’ examples.
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The f-block elements are known as ____________.
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There is a greater range of oxidation states among the actinoids than among the lanthanides.
In lanthanoid the last electron enters (n - 2)f subshell where n is equal to ______.
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.
Assertion: There is a continuous increase in size among Lanthanoids with an increase in atomic number.
Reason: Lanthanoids do not show Lanthanoid contraction.
