Hunds Rule and the Aufbau Principle

Aufbau comes from the German word for build up.  

Sulfur may be an important element in emerging lighting technology. What is the electron configuration of a sulfur atom  

We use the energy ordering and number of orbitals for each subshell to arrive at the overall electron configuration. Then using Hund s rule, we can predict the detailed electron configuration for an atom of sulfur. 

For the detailed configuration, we must consider how to distribute the four electrons in the 3p subshell. We imagine placing the first three electrons each into separate 3p orbitals and then filling one of those orbitals by adding the fourth electron. The resulting configuration is shown below. 

We will discuss the connections between electron configftration and chemical bonding in detail in the next chapter. 

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