atomic number 111 vs roentgenium

atomic number 111 and roentgenium both are nouns.

Word	Noun	Adjective	Verb	Adverb
atomic number 111	Yes	No	No	No
roentgenium	Yes	No	No	No

As nouns, atomic number 111 and roentgenium are synonyms defined as:

atomic number 111 and roentgenium: a radioactive transuranic element, with atomic number 111

Other synonyms of atomic number 111 include element 111, Rg.

atomic number 111 (noun)	roentgenium (noun)
a radioactive transuranic element, with atomic number 111	a radioactive transuranic element, with atomic number 111