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Orbital Box Diagram

Posted: Thu Oct 24, 2019 8:32 pm
by Melvin Reputana 1L
When drawing the orbital box diagram of an atom, an unpaired electron in an orbital would have a spin that is represented by an up arrow correct? Can it ever be a down arrow first?

Re: Orbital Box Diagram

Posted: Thu Oct 24, 2019 8:34 pm
by LNgo 1G
Technically it doesn't matter whether the arrow is up or down because it just represents electrons with opposite spins, not in any specific direction, but generally the up arrow goes first.

Re: Orbital Box Diagram

Posted: Thu Oct 24, 2019 8:36 pm
by PranaviKolla2B
Just to confirm, we would draw all the up arrows first for a specific subshell and then start filling in all the down arrows right?

Re: Orbital Box Diagram

Posted: Thu Oct 24, 2019 8:39 pm
by Vicki Liu 2L
An unpaired electron is generally drawn as an up arrow. I think this has to do with the fact that a spin up electron is at a lower energy level than a spin down electron, so it would fill the orbital box first.

Re: Orbital Box Diagram

Posted: Thu Oct 24, 2019 8:43 pm
by Ryan Narisma 4G
Hi Melvin Reputana 1L! When drawing the orbital diagrams I think Dr. Lavelle mentioned that you can use either the up arrow or down arrow as long as you are consistent. Take for example nitrogen. Nitrogen's (N) electron configuration is 1s^2 2s^2 2p^3. In the first two orbital diagrams (1s and 2s), you would have one up and one down arrow in each diagram as noted by the Pauli exclusion principle. When you start to take into account the p-sublevel electrons, you notice that the electrons must occupy three different orbitals as determined by the Aufbau Principle. These three electrons which occupy the 2px, 2py, and 2pz, orbitals must have parallel spins. In other words, they must all be facing up or all be facing down. When the spins are all parallel (either all up or all down), this indicates that this configuration has the lowest energy, which is most favorable. If the spins were different, then the energy of the atom would be different which does not give you the GROUD state electron configuration. Note that the ground state refers to the electron configuration with the LOWEST energy possible. I hope this helps!

Re: Orbital Box Diagram

Posted: Fri Oct 25, 2019 1:31 pm
by Kassidy Ford 1I
PranaviKolla3G wrote:Just to confirm, we would draw all the up arrows first for a specific subshell and then start filling in all the down arrows right?

Yes, this is because you would fill all unpaired electrons first, and when electrons are unpaired they have parallel spin. then, when you go to fill in the pairs you would draw down arrows, because paired electrons have opposite spins