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प्रश्न
Justify the position of lanthanides and actinides in the periodic table.
उत्तर
Lanthanides:
1. The actual position of lanthanides in the periodic table is group number 3 and period number 6.
2. In the sixth period, the electrons are preferentially filled in the inner 4f sub shell.
3. The fourteen elements following lanthanum (Ce to Lu) show similar chemical properties.
4. Hence they are grouped together and placed at the bottom of the periodic table.
5. This position is justified as follows:
- General electronic configuration: [Xe] 4f1-14 5d0-1 6S2
- Common Oxidation state: +3
- They have similar physical and chemical properties.
Actinides:
1. The actual position of actinides in the periodic table is group number 3 and period number 7.
2. In the seventh period, the electrons are preferentially filled in the inner 5f Sub shell.
3. The fourteen elements following actinides (Th to Lr) show similar chemical properties.
4. Hence they are grouped together and placed at the bottom of the periodic table.
5. This position is justified as follows:
- General electronic configuration: [Rn] 5f2-14 6d0-2 7S2
- Common oxidation state: +3
- They have similar physical and chemical properties.
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संबंधित प्रश्न
Assertion: Ce4+ is used as an oxidizing agent in volumetric analysis.
Reason: Ce4+ has the tendency of attaining +3 oxidation state.
The actinoid elements which show the highest oxidation state of +7 are ____________.
Which one of the following is not correct?
What are actinoids? Give three examples.
Compare lanthanoids and actinoids.
Actinoid contraction is greater from element to element than the lanthanoid contraction, why?
The electronic configuration of gadolinium (Atomic number 64) is ______.
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?
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.
The elements with atomic numbers 35, 53 and 85 are all ______.
Electronic configuration, [Ne] 3s2 3p4 is for ______.
