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Questions
What are actinoids? Give three examples.
What are actinoids?
What are actinoids? Give two examples of actinoids.
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Solution 1
- 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.
Solution 2
- The second series of rare earths, or the second inner transition series, is another name for the actinoid series.
- This series, which includes fourteen elements ranging from thorium (Th, At. No. = 90) to lawrencium (Lr, At. No. = 103), involves the filling of 5f-orbitals in the atoms.
- These elements have physical and chemical characteristics that are very similar to those of actinium (Ac, At. No. = 89), which comes after it in the periodic table. They are called actinoids for this reason.
Notes
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