# What is the electron dot structure for Au/gold and why?

Jun 23, 2017

$\text{Au}$ $\cdot$

#### Explanation:

Gold/Au (atomic number $79$) has only one electron in its outer valence shell.

The $10 \times$ $5 d$ electrons in gold are in a filled energy level, leaving only one electron in the outer shell. The ground state configuration of Gold is

$\left[X e\right] 5 {d}^{10} 6 {s}^{1}$

The energy level difference between the $6 s$ and $5 d$ is small. This makes it possible for one of the two $6 s$ electrons to rather be in the $5 d$ orbitals.

When the $5 d$ has $10$ electrons, the $5 d$ orbitals are filled. The filled $5 d$ orbitals make gold very stable.

Furthermore, the $6 s$ orbital contracts due to scalar relativistic effects (where the $6 s$ electrons move at about half the speed of light), becoming relatively inaccessible to many reactants, making gold quite inert.