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प्रश्न
On the basis of Lanthanoid contraction, explain the following:
Nature of bonding in \[\ce{La2O3}\] and \[\ce{Lu2O3}\] .
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उत्तर
As per fajan’s rule, smaller the size of ion, greater is its tendency to make covalent bonds as the positively charged cation strongly attract the negatively charged electron cloud.
On moving from \[\ce{La}\] to \[\ce{Lu}\] in the lanthanoid series, the atomic size decreases so the covalent character increases. Hence, \[\ce{La2O3}\] is ionic and \[\ce{Lu2O3}\] is covalent.
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संबंधित प्रश्न
Define lanthanoid contraction.
Which among the following pairs of elements is 'not' an example of chemical twins?
Compare the chemistry of actinoids with that of the lanthanoids with special reference to atomic and ionic sizes.
Write the electronic configurations of the element with the atomic number 61.
Write the different oxidation states of iron
What are the consequences of lanthanoid contraction?
Explain the cause of Lanthanoids contraction.
What is the action of the following on lanthanoids?
a. water
b. Sulphur, heat
c. nitrogen, heat
Gadolinium belongs to 4f series. It’s atomic number is 64. Which of the following is the correct electronic configuration of gadolinium?
Although Zr belongs to 4d and Hf belongs to 5d transition series but it is quite difficult to separate them. 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 |
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 |
Which of the following pairs has the same ionic size?
Zr (Z = 40) and Hf (Z = 72) have similar atomic and ionic radii because of ______.
The lathanide ion that would show colour is ______.
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.
The pair of lanthanoid ions which are diamagnetic is:
