Advertisements
Advertisements
प्रश्न
Account for the following :
Zr and Hf have almost similar atomic radii.
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
Which among the following pairs of elements is 'not' an example of chemical twins?
What are the different oxidation states exhibited by the lanthanoids?
Compare the chemistry of actinoids with that of the lanthanoids with special reference to atomic and ionic sizes.
Write the electronic configurations of the elements with the atomic numbers 61, 91, 101 and 109.
What is lanthanoid contraction?
Account for the following:
Zn, Cd and Hg are soft metals.
On the basis of Lanthanoid contraction, explain the following:
Trends in the stability of oxo salts of lanthanoids from \[\ce{La}\] to \[\ce{Lu}\].
In lanthanoid the last electron enters (n - 2)f subshell where n is equal to ______.
Cerium (Z = S8) is an important member of lanthanoids. Which of the following statements about cerium is incorrect?
State a reason for the following:
La(OH)3 is more basic than Lu(OH)3.
