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प्रश्न
Account for the following :
Zr and Hf have almost similar atomic radii.
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उत्तर
Due to lanthanide contraction, Zr and Hf have almost similar atomic radii. It can be explained on the basis of shielding effect. The electrons present in inner shells, shield the outer electrons from nuclear charge, making them experience a low effective nuclear charge. The shielding effect exerted by the electrons decreases in the order s > p > d > f. The f subshell poorly shields the outer electrons from nuclear attraction, which results in more attractive pull of nucleus on outer electron. In case of post lanthanide elements like Hf, 4f subshell is filled and it is not very effective at shielding the outer shell electrons. Therefore, Zr and Hf have almost similar atomic radii.
संबंधित प्रश्न
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.
Write the different oxidation states of iron
Account for the following:
Zn, Cd and Hg are soft metals.
What is lanthanoid contraction? Write the.............
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) \[\ce{Ho}\]
On the basis of Lanthanoid contraction, explain the following:
Stability of the complexes of lanthanoids.
Zr (Z = 40) and Hf (Z = 72) have similar atomic and ionic radii because of ______.
Write any two consequences of Lanthanoid Contraction.
Cerium (Z = S8) is an important member of lanthanoids. Which of the following statements about cerium is incorrect?
Mention uses of alloys.
