atomic number 54 vs inert gas

atomic number 54 and inert gas both are nouns.

Word	Noun	Adjective	Verb	Adverb
atomic number 54	Yes	No	No	No
inert gas	Yes	No	No	No

As nouns, inert gas is a hypernym of atomic number 54; that is, inert gas is a word with a broader meaning than atomic number 54:

atomic number 54: a colorless odorless inert gaseous element occurring in the earth's atmosphere in trace amounts
inert gas: any of the chemically inert gaseous elements of the helium group in the periodic table

Other hypernyms of atomic number 54 include argonon, noble gas.

atomic number 54 (noun)	inert gas (noun)
a colorless odorless inert gaseous element occurring in the earth's atmosphere in trace amounts	any of the chemically inert gaseous elements of the helium group in the periodic table