Assertion: actinium's electron | /r/CapableOf | appear for first time
Facets:
value: in its structure
type: LOCATION
Source sentences:
text: Lanthanum has the advantage of incumbency since the 5d1 electron appears for the first time in its structure whereas it appears for the third time in lutetium, having also made a brief second appearance in gadolinium (though similar logic would also lead to thorium getting the 6d2 position, having incumbency over rutherfordium).[citation needed]