Which is the correct ground-state electron configuration for gold?

Which is the correct ground-state electron configuration for gold?

• A. [Xe] 6s2 4f14 5d10
• B. [Xe] 6s2 4f14 5d9
• C. [Xe] 6s2 4f14 5d11
• D. [Xe] 6s1 4f14 5d10

Answer: (D)

This question is testing how heavy elements are arranged in their ground-state electron configuration, especially why gold ends up with one electron in the 6s orbital and a full 5d subshell. Gold has 79 electrons, and after the xenon core (54 electrons) there are 25 electrons to place. The most stable arrangement places 14 electrons in the 4f subshell, 10 electrons in the 5d subshell, and a single electron in the 6s orbital. This yields the configuration [Xe] 4f14 5d10 6s1, or equivalently written as [Xe] 6s1 4f14 5d10, which is the form shown in the option. The key idea is that a full d subshell (5d10) plus a single electron in the 6s orbital provides a particularly low-energy, stable arrangement for gold, matching experimental data and the element’s chemical behavior.

This question is testing how heavy elements are arranged in their ground-state electron configuration, especially why gold ends up with one electron in the 6s orbital and a full 5d subshell. Gold has 79 electrons, and after the xenon core (54 electrons) there are 25 electrons to place. The most stable arrangement places 14 electrons in the 4f subshell, 10 electrons in the 5d subshell, and a single electron in the 6s orbital. This yields the configuration [Xe] 4f14 5d10 6s1, or equivalently written as [Xe] 6s1 4f14 5d10, which is the form shown in the option. The key idea is that a full d subshell (5d10) plus a single electron in the 6s orbital provides a particularly low-energy, stable arrangement for gold, matching experimental data and the element’s chemical behavior.