5d–series consists of elements La (atomic number 57) and from Hf (atomic number 72) to Hg (atomic number 80). These elements lie in the 6th period. The elements of this series involve the gradual filling of 5d orbitals. In between La₅₇ and Hf₇₂, there are 14 elements viz. Ce₅₈ to Lu₇₁ which are called lanthanides or lanthanones. These 14 elements involve the progressive filling of 4f orbitals and hence do not belong to 5d series. Thus at Lu₇₁, 4f orbitals are completely filled. Consequently at La₅₇, 4f orbitals are vacant (4f⁰ configuration) while in the remaining nine elements (Hf₇₂ to Hg₈₀) 4f orbitals are completely–filled (4f¹⁴ configuration).

The elements namely Pt₇₈ and Au₇₉ (two elements) have anomalous configurations.

Complete and valence–shell electronic configurations of the atoms of 5d–series elements can be written as follows. Here [Xe]₅₄ = 2, 8, 18, 18, 8 (five–shells).

Complete configuration = [Xe]₅₄ 4f^0,14 5d ^1–106s²; which is otherwise written as 2, 8, 18, 4s²p⁶ d¹⁰f^0–14, 5s²p⁶d^1–10, 6s² (six shells). Valence–shell configuration = 4f^0–14 5d^1–10 6s².

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