actinide

Examples of actinide in the following topics:

• Lanthanides and Actinides

  • Lanthanides and actinides are elements of the inner transition series of the periodic table.
  • Actinides are typical metals.
  • Like the lanthanides, all actinides are highly reactive with halogens and chalcogens; however, the actinides react more easily.
  • Actinides, especially those with a small number of 5f electrons, are prone to hybridization.
  • Most actinides exhibit a larger variety of valence states.

• The Bottom of the Periodic Table

  • By expanding the horizontal dimensions of the table, the actinide and lanthanide rows can be put into their correct relative positions.
  • Taking the extension of the periodic table even further, consider an element with atomic number 92 in the actinide series, called uranium.
  • In 1934 only 4 actinides were known, all smaller than uranium, so it was not known that they formed a period or family like the lanthanides.
  • The actinides were added along with the lanthanides.
  • The lanthanides and actinides are added as separate but connected rows, building what is called the f-block.

• The Periodic Table of Elements

  • Although groups generally have more significant periodic trends, there are regions where horizontal trends are more significant than vertical group trends, such as in the f-block, where the lanthanides and actinides form two substantial horizontal series of elements.

• Carbides

  • Carbides of the actinide elements, which have the structure MC2 and M2C3, are also described as salt-like derivatives of C22-.

• General Trends in Chemical Properties

  • The f block, usually offset below the rest of the periodic table, includes the lanthanides and actinides.

• Coordination Number, Ligands, and Geometries

  • Due to their large size, lanthanides, actinides, and early transition metals tend to have high coordination numbers.