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प्रश्न
What are actinoids? Give three examples.
उत्तर
- The fourteen elements following actinium, i.e., from thorium (Th) to lawrencium (Lr) are called actinoids.
- All the actinoids are radioactive and most of them have short half-lives.
- The heavier members being extremely unstable and not of natural occurrence. They are produced synthetically by the artificial transformation of naturally occurring elements by nuclear reactions.
- Example: Thorium, Uranium, Plutonium, Californium.
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संबंधित प्रश्न
Which of the following oxidation states is most common among the lanthanoids?
The most common oxidation state of actinoids is ____________.
Which one of the following is not correct?
What are inner transition elements?
Compare lanthanoids and actinoids.
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?
Illustrate by taking examples of transition elements and non-transition elements that oxidation states of elements are largely based on electronic configuration.
