Assertion: metal's form | /r/HasProperty | defended on ground
Facets:
Source sentences:
text: The form with lanthanum under yttrium has been defended on the grounds that lanthanum and actinium in their ground-state configurations (respectively [Xe]5d16s2 and [Rn]6d17s2) have no electrons in f subshells and therefore should not be placed in the f-block.