So first, we distribute the three electrons the following way. We place one into P, one into Y, and then one into D. And now, since all of them are filled, my fourth electron will go into filling completely this orbital. This PX orbital. For example, if I dealt with the next atom, if I had one more electron, I place it into this y and if I had one more electron, I place it into my Z and I get a noble gas configuration. So Hans Rule can be represented in the following graphic way. So let's look at nitrogen.