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प्रश्न
Gadolinium belongs to 4f series. It’s atomic number is 64. Which of the following is the correct electronic configuration of gadolinium?
विकल्प
\[{[Xe] 4f^75d^16s^2}\]
\[{[Xe] 4f^65d^26s^2}\]
\[{[Xe] 4f^86d^2}\]
\[{[Xe] 4f^95d^1}\]
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उत्तर
\[{[Xe] 4f^75d^16s^2}\]
Explanation:
Gadolinium belongs to the 4f series; it has atomic no.= 64. It has extra stability due to a half-filled 4f subshell.
\[\ce{Gd (Z = 64) -> [Xe] 4f^6 5d^2 6s^2}\]
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संबंधित प्रश्न
Define lanthanoid contraction.
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Account for the following :
Zr and Hf have almost similar atomic radii.
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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.
Name the members of the lanthanoid series which exhibit +4 oxidation state and those which exhibit +2 oxidation state. Try to correlate this type of behavior with the electronic configurations of these elements.
Explain, why lanthanum (Z = 57) forms La3+ ion, while cerium (Z = 58) forms Ce4+ ion?
The f-block elements are known as ____________.
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+
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 |
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Radii of 4d and 5d block elements.
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 ______.
Cerium (Z = S8) is an important member of lanthanoids. Which of the following statements about cerium is incorrect?
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(Atomic numbers of Mn = 25 and Fe = 26)
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.
