Question #8926c

1 Answer
Sep 3, 2017



The definition of quantum spin is #"+/-" (1/2)#. A fractional quantum spin thus can only exist when there are unpaired electrons.

The only element of the selection that has paired electrons in its valence shell is Oxygen-16, with an electron configuration of
#1s^2 2s^2 2p^4#

All of the others have an uneven number of valence electrons, and therefore an unpaired electron.