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Question
What is lanthanoid contraction? Write the.............
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Solution
The regular decrease in atomic and ionic radii from lanthanum to lutetium with increasing atomic number is called lanthanoid contraction.
Consequences :
The net result of the lanthanoid contraction is that the second and third d-series exhibit similar radii
Zr =160 pm
and Hf = 159pm
They have very similar physical and chemical properties.
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RELATED QUESTIONS
Define lanthanoid contraction.
What are chemical twins? Write ‘two’ examples.
Name a member of the lanthanoid series which is well known to exhibit +4 oxidation state.
Write the different oxidation states of iron
Account for the following:
Zn, Cd and Hg are soft metals.
What is meant by Lanthanide contraction? Write the general electronic configuration of inner transition elements.
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 |
On the basis of Lanthanoid contraction, explain the following:
Nature of bonding in \[\ce{La2O3}\] and \[\ce{Lu2O3}\] .
Which one of the lanthanoids given below is the most stable in divalent form?
Assertion: There is a continuous increase in size among Lanthanoids with an increase in atomic number.
Reason: Lanthanoids do not show Lanthanoid contraction.
