Rules for Electronic Configuration

Aufbau pirnciple:

Rules for Electronic Configuration

Electrons must fill orbitals starting with the lowest energy level available. The order is shown in the image to the right.

There are a few exceptions, so be careful!!

Pauli Exclusion Principle:

If there are two electrons in the same orbital, they must spin in opposite directions

Don't want them crashing into each other!!

Hund's Rule:

The orbitals of the subshells are filled singly before any are filled doubly

This is often called the bus-seat rule because people tend to fill the double seats on the bus singly rather than sit beside somebody they don't know!

Rules for Electronic Configuration