e- Configuration for Carbon

[Briana Chavez 3F]

Hello everyone!

In the week 3 Friday lecture, while the professor was explaining electron configurations, I was still a bit confused about why the arrows were facing certain directions for Carbon. Can anyone clarify why both of the arrows in 2p are going up (as opposed to up-down like the arrows in 2s and 1s)?
For reference, the chart looked like this (to the best of my ability):
2p: ^ ^
2s: ^v ^v
1s: ^v ^v

[loganchun]

Hi, they are both pointing upwards because of Hund's rule. Due to electron repulsion, the electrons prefer to be in their own orbital before they pair up. They will be parallel in their own orbitals until all three are filled up with one electron each like this ^ ^ ^. If they pair up first, the electron repulsion from the pair of electrons is more unstable than if the electrons were alone in their orbital.

[Kimia Rategh 2A]

Hi!

So due to Hund's Rule, we always fill each orbital in a shell with a single electron (normally with an upward spin, though I think you can also start with a down spin if I am not mistaken) before going back and fully filling each orbital with an electron of each spin. This is because of electron repulsions leading electrons to be parallel to each other before being paired. In the case of carbon, since there are not enough electrons to fully fill the 2p orbital, the final 2 electrons are simply placed in two different orbitals each with an upward spin. Hope this helps!

[Claire Kim 1F]

Hello everyone!

In the week 3 Friday lecture, while the professor was explaining electron configurations, I was still a bit confused about why the arrows were facing certain directions for Carbon. Can anyone clarify why both of the arrows in 2p are going up (as opposed to up-down like the arrows in 2s and 1s)?
For reference, the chart looked like this (to the best of my ability):
2p: ^ ^
2s: ^v ^v
1s: ^v ^v

I believe it's due to Hund's Rule. Each orbital needs an up arrow before pairing up with a down arrow. That's why both of the arrows in 2p are facing up and other orbitals have an up and down arrow.

[Kathryn Heinemeier 3H]

It's because of Hund's rule because it is more stable when the electrons are separate and not in a pair because there is repulsion between them. As s result, you fill in the other orbitals first and once those are filled you then start pairing the electrons up.

[Caitlyn Lo 2F]

This happens because of Hund's rule. The electrons prefer to be in their own orbitals first before pairing up so when making an electron configuration, the electrons fill all of the orbitals first before pairing up.

[Alyssa Cua 2J]

Hi, they are both pointing upwards because of Hund's rule. Due to electron repulsion, the electrons prefer to be in their own orbital before they pair up. They will be parallel in their own orbitals until all three are filled up with one electron each like this ^ ^ ^. If they pair up first, the electron repulsion from the pair of electrons is more unstable than if the electrons were alone in their orbital.

This is a great explanation! Thank you for clarifying! :)

[Marie Khijniak 2E]

Hi!
Whenever you draw electron configurations, first each orbital has to have one electron in it, before they can be doubled up. For example for the p-orbitals, each orbital will have one electron, ands then after if there are more, you can double up the electrons in the orbitals. This is because of Hund’s Rule that tries to pout the electron configurations into the lowest ground state possible. If there are two electrons in an orbital, there is a repulsion force between their like-charges that has to be countered to keep the atom stable, requiring more energy than when there is only on electron per orbital. You can either draw all of the electrons going up, or down, the only key is that in each orbital if there are two directions, they have to be rotating in opposite directions (up and down).
Hope this helps :)

[Erin Woolmore 1C]

One electron needs to occupy each sublevel before being paired. For example, Carbon's electron configuration is 1s^2 2s^2 2p^2. The 2p level has 3 sublevels, with room for 2 electrons in each for a total of 6 electrons in the 2p level. Since there are only 2 electrons in the 2p level, you have to place one in 2px, then one in 2py. These are unpaired. (If there was one more electron (like in Nitrogen), there is one electron in the 2pz sublevel. Oxygen has 8 electrons, so now you can start pairing, and there would be 2 in the 2px sublevel.) As for the arrows, unpaired electrons have the same spin, while paired electrons have opposite spins.

[Prithvi Raj 3E]

The professor is following Hund’s rule. According to this rule, every electron fills up one orbital before doubling up. As a result, you have two electrons pointing up as you haven’t filled up every orbital with one electron.

[Brooke Gushiken 1B]

Hi! This configuration is due to Hund's rule, which states that each orbital sublevel must be filled with one electron before they start pairing up, and their spins are also parallel to each other. For Carbon, since it only has two 2 electrons in the 2p level, it fills 2px and 2py with one electron each and both unpaired electrons have a spin in the same direction (upward).