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प्रश्न
Actinoid contraction is greater from element to element than the lanthanoid contraction, why?
उत्तर
- Actinoid contraction is greater from element to element than lanthanoid contraction. The 5f orbitals in Actinoids have a very poorer shielding effect than 4f orbitals in lanthanoids.
- Thus, the effective nuclear charge experienced by electrons in valence shells in the case of actinoids is much more than that experienced by lanthanoids.
- In actinoids, electrons are shielded by 5d, 4f, 4d and 3d whereas in lanthanoids, electrons are shielded by 4d, 4f only.
- Hence, the size contraction in actinoids is greater as compared to that in lanthanoids.
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संबंधित प्रश्न
Which one of the following statements related to lanthanons is incorrect?
Which of the following oxidation states is most common among the lanthanoids?
What is lanthanoid contraction and what are the effects of lanthanoid contraction?
Compare lanthanoids and actinoids.
Why do zirconium and Hafnium exhibit similar properties?
Which of the following is not an actinoid?
The electronic configuration of gadolinium (Atomic number 64) is ______.
The elements in which electrons are progressively filled in 4f-orbital are called ______.
In the modern periodic table, elements are arranged in order of increasing atomic numbers which is related to the electronic configuration. Depending upon the type of orbitals receiving the last electron, the elements in the periodic table have been divided into four blocks, viz, s, p, d and f. The modern periodic table consists of 7 periods and 18 groups. Each period begins with the filling of a new energy shell. In accordance with the Arfbau principle, the seven periods have 2, 8, 8, 18, 18, 32 and 32 elements respectively. The seventh period is still incomplete. To avoid the periodic table being too long, the two series of f-block elements, called lanthanoids and actinoids are placed at the bottom of the main body of the periodic table.
Which of the elements whose atomic numbers are given below, cannot be accommodated in the present set-up of the long form of the periodic table?
Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R:
Assertion A: Size of Bk3+ ion is less than Np3+ ion.
Reason R: The above is a consequence of the lanthanoid contraction.
In the light of the above statements, choose the correct answer from the options given below:
