atomic number 61 vs Pm

atomic number 61 and Pm both are nouns.

Word	Noun	Adjective	Verb	Adverb
atomic number 61	Yes	No	No	No
Pm	Yes	No	No	No

As nouns, atomic number 61 and Pm are synonyms defined as:

atomic number 61 and Pm: a soft silvery metallic element of the rare earth group having no stable isotope; was discovered in radioactive form as a fission product of uranium

Other synonyms of atomic number 61 include promethium.

atomic number 61 (noun)	Pm (noun)
a soft silvery metallic element of the rare earth group having no stable isotope; was discovered in radioactive form as a fission product of uranium	a soft silvery metallic element of the rare earth group having no stable isotope; was discovered in radioactive form as a fission product of uranium