Assertion: noble gas | /r/HasProperty | discovered
Facets:
value: first twice
type: TEMPORAL
Source sentences:
text: Noble gases were discovered, but not properly named or recognized, in 1785 by Henry Cavendish.
text: That’s why helium, one of the first noble gases to be discovered, doesn’t react with the rubber of the balloon that holds it.
text: At the moment the article suggests that the noble gases were discovered first twice : as argon in the air and helium in the sun.
text: This chemical property of this first noble gas to be discovered impressed the namers.
text: As a result, they were the last elements to be discovered.