Electron Spin

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Rishika Yadav 3D
Posts: 53
Joined: Wed Sep 11, 2019 12:17 am

Electron Spin

Postby Rishika Yadav 3D » Sun Oct 20, 2019 5:02 pm

Can someone please explain why two electrons have a different spin if they are paired versus if they are parallel?

Posts: 115
Joined: Thu Jul 11, 2019 12:16 am

Re: Electron Spin

Postby SVajragiri_1C » Sun Oct 20, 2019 5:11 pm

According to Hund's Rule, electrons occupy empty orbitals in the same subshell before they start to pair up. When this happens, the spins are all parallel(the same). Once all orbitals are filled, the electrons start pairing up:
According to the Pauli Exclusion principle, each orbital can only be occupied by two electrons with opposite spins (this means they are paired).

Charisse Vu 1H
Posts: 101
Joined: Thu Jul 25, 2019 12:17 am

Re: Electron Spin

Postby Charisse Vu 1H » Sun Oct 20, 2019 5:28 pm

When two electrons are paired, it means that they exist in the same orbital within a subshell. When electrons are parallel, they are filling the orbitals singly before pairing. According to Hund's Rule, this happens because when there are two or more orbitals with equal energies, electrons will fill them singly before pairing with each other for stability. Atoms in their ground states want to have as many unpaired electrons as possible. Also, according to the Pauli Exclusion principle, electrons must be of opposite spin if they occupy the same orbital. Therefore, paired electrons must have opposite spin (Pauli Exclusion Principle) and parallel electrons have the same spin (Hund's Rule).

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