Definition

Noun: 1. A specific group of chemical elements: The actinide series is the set of 15 metallic, radioactive elements with consecutive atomic numbers from 89 (actinium) to 103 (lawrencium). These elements are characterized by the filling of their 5f electron orbitals.

Usage

The term is used primarily in scientific contexts, specifically chemistry and nuclear physics, to categorize and discuss this specific block of elements on the periodic table. - The actinide series is placed below the main body of the periodic table. - Plutonium and uranium are the most well-known members of the actinide series. - Scientists study the chemical properties of the entire actinide series.

Examples

• In nuclear reactors, several elements from the actinide series are produced as byproducts.
• The disposal of waste containing the actinide series presents a significant long-term challenge.
• Her research focuses on the complex coordination chemistry of the later actinide series elements.

Advanced Usage

• "Transuranic elements": This term refers specifically to the elements in the actinide series with atomic numbers 92 (uranium). All transuranic elements are part of the actinide series, but not all actinides are transuranic (e.g., thorium, protactinium, uranium).
  • Most transuranic elements in the actinide series are synthetic and do not occur naturally in significant quantities.

Variants and Related Words

• Actinide (noun): Any individual element belonging to the actinide series.
  • Plutonium is an actinide.
• Actinoid (noun): A synonym for "actinide," often used interchangeably.

Synonyms

• Actinoids: A synonym for the actinide series.
• 5f series: A technical term referencing the electron orbital being filled.

Related Concepts

• Lanthanide series: The series of 15 elements with atomic numbers 57 (lanthanum) to 71 (lutetium), which fill their 4f orbitals. It is the series directly above the actinide series on the periodic table, and the two are often compared.
• Inner transition metals: A broader category that includes both the lanthanide and actinide series.

Noun

1. (chemistry) a series of 15 radioactive elements with increasing atomic numbers from actinium to lawrencium