Gold is element number 79 with symbol “Au”. The observed electron configuration of “Au” gold is: {Xe core] 4f 14 5d 10 6s1. Instead of classical physics: [Xe core] 4f 14 5d 9 6s 2. The difference between the two formula is the “6s” orbital is 2 and “filled” in classical chemistry. “Element Electron Configuration Taste Traits” is a post in this blog with related ideas.