What is the Difference Between Actinides and Lanthanides?

06/23/2025 • Giovanni Medeiros

Actinides and lanthanides are two groups of elements with unfilled f orbitals, often referred to as inner transition metals. They have some similarities, but there are key differences between them:

Lanthanides:

  1. Act as metals with reactivity similar to group 2 elements.
  2. Consist of elements with atomic numbers 58 to 71.
  3. Lanthanides have high melting and boiling points and react with water to produce hydrogen gas.
  4. They are used in optical devices, night vision goggles, petroleum refining, and alloys.

Actinides:

  1. Consist of elements from atomic numbers 89 to 103, with the exception of thorium and uranium, all are radioactive.
  2. Have dense masses and are mainly used in applications where their radioactivity can be harnessed for energy generation.
  3. Actinides show greater tendency to form complexes compared to lanthanides.
  4. They are employed in nuclear weapons, power plants, and are radioactive.

In summary, lanthanides are all metals with reactivity similar to group 2 elements and are used in various applications, while actinides are radioactive elements primarily used in applications that harness their radioactivity for energy generation.

Comparative Table: Actinides vs Lanthanides

Below is a table comparing the differences between actinides and lanthanides:

Property Lanthanides Actinides
Position in the periodic table Two rows below the main body of the periodic table Two rows below the lanthanides in the periodic table
Atomic numbers 58 to 71 89 to 103
Radioactivity One lanthanide, Promethium, is radioactive All actinides are radioactive
Electron configuration electrons are added to the 4f sublevel electrons are added to the 5f sublevel
Common names Also known as rare earth elements Sometimes referred to as inner transition elements
Applications Lanthanides are used in various applications, such as electronics, magnets, and lasers Actinides are primarily used in nuclear chemistry and energy production

Both lanthanides and actinides are considered inner transition elements, as they have partially filled f subshells and are placed in separate rows below the main body of the periodic table. They play significant roles in various applications, including electronics, magnets, lasers, and nuclear energy production.

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