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प्रश्न
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) \[\ce{Ho}\]
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उत्तर
(ii) \[\ce{Eu}\]
(iii) \[\ce{Yb}\]
Explanation:
\[\ce{Ce}\] (Z = 57) = [Xe] 4f5 5d0 6s2, O.S. = + 3, + 4
\[\ce{Eu}\] (Z = 63) = [Xe] 4f7 5d0 6s2, O.S. = + 2, + 3
\[\ce{Yb}\] (Z = 70) = [Xe] 4f14 5d0 6s2, O.S. = + 2, + 3
\[\ce{Ho}\] (Z = 67) = [Xe] 4f11 5d0 6s2, O.S. = + 3
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संबंधित प्रश्न
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a. water
b. Sulphur, heat
c. nitrogen, heat
The f-block elements are known as ____________.
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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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| Column I (Property) | Column II (Element) | |
| (i) | Lanthanoid which shows +4 oxidation state |
(a) Pm |
| (ii) | Lanthanoid which can show +2 oxidation state |
(b) Ce |
| (iii) | Radioactive lanthanoid | (c) Lu |
| (iv) | Lanthanoid which has 4f7 electronic configuration in +3 oxidation state |
(d) Eu |
| (v) | Lanthanoid which has 4f14 electronic configuration in +3 oxidation state |
(e) Gd |
| (f) Dy |
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La(OH)3 is more basic than Lu(OH)3.
Mention uses of alloys.
