Assertion: atom's electron | /r/CapableOf | pair up with each other
Facets:
value: due to the nature of electrons
type: CAUSE
Source sentences:
text: Due to the nature of electrons to obey the Pauli exclusion principle, in which no two electrons may be found in the same quantum state, bound electrons pair up with each other, with one member of each pair in a spin up state and the other in the opposite, spin down state.