atomic number 68 vs erbium

atomic number 68 and erbium both are nouns.

Word	Noun	Adjective	Verb	Adverb
atomic number 68	Yes	No	No	No
erbium	Yes	No	No	No

As nouns, atomic number 68 and erbium are synonyms defined as:

atomic number 68 and erbium: a trivalent metallic element of the rare earth group; occurs with yttrium

Other synonyms of atomic number 68 include Er.

atomic number 68 (noun)	erbium (noun)
a trivalent metallic element of the rare earth group; occurs with yttrium	a trivalent metallic element of the rare earth group; occurs with yttrium