yttrium vs atomic number 39

yttrium and atomic number 39 both are nouns.

Word	Noun	Adjective	Verb	Adverb
yttrium	Yes	No	No	No
atomic number 39	Yes	No	No	No

As nouns, yttrium and atomic number 39 are synonyms defined as:

yttrium and atomic number 39: a silvery metallic element that is common in rare-earth minerals; used in magnesium and aluminum alloys

Other synonyms of yttrium include Y.

yttrium (noun)	atomic number 39 (noun)
a silvery metallic element that is common in rare-earth minerals; used in magnesium and aluminum alloys	a silvery metallic element that is common in rare-earth minerals; used in magnesium and aluminum alloys