Block (periodic table)

Blocks s, f, d, and p in the periodic table

A block of the periodic table is a set of elements unified by the atomic orbitals their valence electrons or vacancies lie in.[1] The term seems to have been first used by Charles Janet.[2] Each block is named after its characteristic orbital: s-block, p-block, d-block, f-block and g-block.

The block names (s, p, d, and f) are derived from the spectroscopic notation for the value of an electron's azimuthal quantum number: sharp (0), principal (1), diffuse (2), and fundamental (3). Succeeding notations proceed in alphabetical order, as g, h, etc., though elements that would belong in such blocks have not yet been found.

  1. ^ Jensen, William B. (21 March 2015). "The positions of lanthanum (actinium) and lutetium (lawrencium) in the periodic table: an update". Foundations of Chemistry. 17: 23–31. doi:10.1007/s10698-015-9216-1. S2CID 98624395.
  2. ^ Charles Janet, La classification hélicoïdale des éléments chimiques, Beauvais, 1928