Elements for Kids
Lanthanides and Actinides
The lanthanides and actinides are groups of elements in the periodic table. They are the elements that are often listed below the main section of the periodic table. There are thirty total elements in the lanthanides and actinides. They are often called the "inner transition metals."
The lanthanides are the elements with atomic numbers from 57 to 71. These 15 metals (along with scandium and yttrium) are often called the rare earth elements. They are all silvery-white metals which are often found in the same ores. They are called the lanthanides because they exhibit similar chemical properties to lanthanum, the first element in the group.
Actinides are the 15 elements with atomic numbers from 89 to 103. They are named after the first element in the series, actinium. The actinides group includes mostly man-made elements with only a few exceptions such as uranium and thorium. The actinides are most known for the elements uranium and plutonium which are used in nuclear reactors and nuclear bombs.
Interesting Facts about Lanthanides and Actinides
- The lanthanides and actinides are located mostly in the "f-block" of the periodic table.
- Lanthanides are used in products such as hybrid cars, superconductors, and permanent magnets.
- The actinide americium is used in smoke detectors.
- Elements that have an atomic number greater than uranium (92) are often called "transuranium." Many of these elements are man-made under the conditions of nuclear reactors.
- The first actinides discovered were uranium and thorium.
- The name "actinium" comes from the Greek word "aktis" which means beam or ray.
- Both actinides and lanthanides are highly reactive with elements from the halogen group.
- All of the lanthanides have at least one stable isotope except for promethium.
- None of the actinides have a stable isotope. They are all radioactive.
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