atomic number 39 vs Y

atomic number 39 and Y both are nouns.

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

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

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

Other synonyms of atomic number 39 include yttrium.

atomic number 39 (noun)	Y (noun)
a silvery metallic element that is common in rare-earth minerals; used in magnesium and aluminum alloys	the 25th letter of the Roman alphabet
	a silvery metallic element that is common in rare-earth minerals; used in magnesium and aluminum alloys