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प्रश्न
What is lanthanoid contraction? Write the.............
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उत्तर
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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संबंधित प्रश्न
What are chemical twins? Write ‘two’ examples.
Compare the chemistry of actinoids with that of the lanthanoids with special reference to atomic and ionic sizes.
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.
What is meant by Lanthanide contraction? Write the general electronic configuration of inner transition elements.
What is the action of the following on lanthanoids?
a. water
b. Sulphur, heat
c. nitrogen, heat
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) \[\ce{Ho}\]
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?
Trivalent Lanthanoid ions such as La3+ (Z = 57) and Lu3+ (Z = 71) do not show any colour in their solution. Give a reason.
