# Electron configuration and the 2p orbital

I looked through the questions already asked about this topic and they were very specific and over my head. I'm having trouble with the basics.

When drawing orbital diagrams I know electrons are placed in the 2p boxes singly first then paired because of they have parallel rotations and the Pauli exclusion principle states that an orbital can only house 2 electrons and those electrons must be of opposite spin. My question is why do electrons behave this way in the 2p orbital but not the 1s or 2s? And why does the p subshell contain three 2p orbitals?

As far as electron configurations and orbital diagrams are concerned I've gotten to Ne and the 2p configuration confused me so I though I'd ask before moving on.

• they have parallel rotations . Electrons do not rotate. They are not little classical balls orbiting the nucleus. why do electrons behave this way in the 2p orbital but not the 1s or 2s. What do you mean by this? The Pauli exclusion principle applies for all electrons. – bon Nov 14 '15 at 20:08
• I mean why do the three 2p orbitals fill singly first then pair up instead one orbital filling up at a time. – Chinasa Nov 14 '15 at 20:25
• Because the 3 p-orbitals are degenerate but putting two electrons into the same orbital (with opposite spin of course) has an energy cost associated with the repulsion between the electrons. – bon Nov 14 '15 at 20:30
• Cross posted to Physics SE. Bad form... – Jon Custer Nov 14 '15 at 20:39
• Thats not allowed? What wrong with different answers from different people? – Chinasa Nov 14 '15 at 20:49

## 1 Answer

first of all electrons do not rotate but they have spins next magnetic quantum number decides how many electrons an orbital can have s can have 2(m=1){consider 1 box} p can have 6(m=3){consider 3 boxes} d can have 10(m=5){consider 5 boxes} f can have 14(m=7){consider 7 boxes} where each box can have at max 2 electrons and each box represents different orientation of the orbital and all the orbitals(except s) have degenerate orbitals, i.e they have the same energy so all have to filled with atleast one electron before pairing up. this rule is known as Hund's Rule of Maximum Multiplicity there are are some more reasons fro it. they are to maximize exchange energy to attain symmetry

• Punctuation is really useful you know. It also doesn't really answer the question. Most of it is just background material about the different quantum numbers. – bon Nov 16 '15 at 18:41