## Same spin

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Ghadir Seder 1G
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Joined: Sat Sep 14, 2019 12:17 am

### Same spin

What does it mean for an electron to have the "same spin?"

JOtomo1F
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### Re: Same spin

Electron spin is an unvarying number of either 1/2 or -1/2. The 1/2 spin applies to an "upward spin" of an electron and is represented in an electron configuration by an upward arrow. The -1/2 spin refers to the "downward spin" of an electron and is represented in an electron configuration by the downward area.

Louise Lin 2B
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Joined: Sat Aug 17, 2019 12:15 am

### Re: Same spin

Adding on to the above comment, two electrons with the "same spin" means that they are both either spinning upward or spinning downward. Take the element carbon: the atomic number is 6, so the electron configuration would be 1s2 2s2 2p2. The 1s and 2s shells are both at the maximum occupancy, but the 2p shell only has 2 electrons. These two electrons would have the same spin.

Kurtis Liang 3I
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### Re: Same spin

It's also helpful to note that all electrons will have the same spin until there is no room in the subshell and electrons must pair up (paired electrons have opposite spin). This is explained by Hund's rule.

Sanjana Borle 2K
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### Re: Same spin

Same spin means that the electrons spin in the same direction (parallel to each other) and have the same quantum number (1/2 or -1/2). According to Hund's rule all electrons that are unpaired in an orbital will have the same, or parallel spin, but if there is more electrons and it requires pairing up, the pairs will spin in different directions.

Drake Choi_1I
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### Re: Same spin

When drawing spin, is there a reason why only half of the arrow point is used?

Hailey Kim 4G
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### Re: Same spin

Drake Choi_1I wrote:When drawing spin, is there a reason why only half of the arrow point is used?

I've seen it done both ways. In high school, I was taught to only draw half of the arrow point but Professor Lavelle draws the whole arrow point. I don't think it really matters as long as the arrow is pointing in the right direction.

Drake Choi_1I
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Joined: Sat Aug 17, 2019 12:15 am

### Re: Same spin

Thank you for the clarification! :)

Aprice_1J
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### Re: Same spin

When would you see them have parallel spins? If they are more stable with different spins, what would constitute them having the same spin?

505306205
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### Re: Same spin

Aprice_1J wrote:When would you see them have parallel spins? If they are more stable with different spins, what would constitute them having the same spin?

Electrons with the same spin cannot occupy the same orbital. Electrons singly occupy the different orbitals with parallel spins (Hund's Rule).

Jasmine Kim 1L
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Joined: Fri Aug 02, 2019 12:16 am

### Re: Same spin

Aprice_1J wrote:When would you see them have parallel spins? If they are more stable with different spins, what would constitute them having the same spin?

Elements such as carbon and nitrogen have parallel spins in the 2p subshell because it has multiple orbitals and electrons with parallel spins typically occupy different orbitals. You can see parallel spins in any subshell with multiple orbitals. I don't know if they have to always have the same spin, but I think they usually do because it is the most stable state for the atom.

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