Questions on exceptions to Aufbau principle.. Please help

[runner940]

Questions on exceptions to Aufbau principle. . . Please help!

Homework Statement

Explain how and why Co and Mo break the Aufbau principle in their respective e- configuration.

Homework Equations

The Attempt at a Solution

I was out of class when my teacher explained this, please help me. . .

 

[Borek]

Do you know what Aufbau principle is? Read about it in your book, you may also consult wikipedia. Then take a look at Co and Mo electron configuration - are these expected when applying Aufbau principle?