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Traductions

• anglais

  Date : 1987

  Définition

  One of the series of concentric spheres, or orbits, at various distances from the nucleus, in which, according to atomic theory, electrons move around the nucleus of an atom.
  
  A term applied by physical chemists to the various energy levels or groups of orbitals occupied by electrons as they revolve around atomic nuclei.

  Notes :

  The shells are designated, in the order of increasing distance from the nucleus, as the K, L, M, N, O, P, and Q shells. The number of electrons which each shell can contain is limited. Electrons in each shell have the same energy leveland are further grouped into subshells.
  
  There are seven possible shells, designated as K, L, M, N, etc.; The number varies with the element from 1 in the lightest (hydrogen and helium). Each shell can contain only a certain number of electrons, for example, 2 for K, 8 for L, 18 for M, and 32 for N; the shell may or may not be completely filled. The outer shell contains the volence electrons, which are directly involved in chemical bonding.

  Terme :

  1. shell