Question

What are actinoids? Give three examples.

What are actinoids?

What are actinoids? Give two examples of actinoids.

Answer 1

1. The fourteen elements following actinium, i.e., from thorium (Th) to lawrencium (Lr) are called actinoids.
2. All the actinoids are radioactive and most of them have short half-lives.
3. 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.
4. Example: Thorium, Uranium, Plutonium, Californium.

Answer 2

1. The second series of rare earths, or the second inner transition series, is another name for the actinoid series.
2. 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.
3. 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.