QuestionAtomic structure / configuration
Which one of the following is the correct electronic configuration of gold (ground state)?
- (a) [Xe] 6s² 4f¹⁴ 5d⁹
- (b) [Xe] 6s¹ 4f¹⁴ 5d¹⁰
- (c) [Xe] 6s² 4f¹³ 5d¹⁰
- (d) [Xe] 6s² 4f¹⁴ 5d¹⁰
Answer: (b) [Xe] 6s¹ 4f¹⁴ 5d¹⁰
Au (Z = 79) is like Cu and Ag: a full d¹⁰ is more stable, so one 6s electron moves to 5d. Ground state: [Xe] 4f¹⁴ 5d¹⁰ 6s¹ → (b). Relativistic contraction of 6s in Au supports this.