Orbital properties spin angular momentum compared

The eighth element of the second period, neon, possesses several chemical peculiarities when compared with the other elements of this series. The total spin angular momentum will be zero, since the spins of the separate electrons in each orbital are antiparallel, and furthermore, the total angular momentum will be zero. Experimental observation of the properties of neon makes it possible to relate the completion of an electronic shell with chemical inactivity. 

Comparing with the commutation relations above, we see that for r and p at least, K has the effect of an antiunitary operator. Expressing orbital angular momentum as f = r X p, we see that = —1. For spin we can draw on the analogies between the transformation of commutation relations for spin and orbital angular momentum. From these we see that the transformed commutation relations are consistent with Cs0 = -s, and the spin has the same transformation properties as orbital angular momentum. 

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