Rb vs atomic number 37

Rb and atomic number 37 both are nouns.

Word	Noun	Adjective	Verb	Adverb
Rb	Yes	No	No	No
atomic number 37	Yes	No	No	No

As nouns, Rb and atomic number 37 are synonyms defined as:

Rb and atomic number 37: a soft silvery metallic element of the alkali metal group; burns in air and reacts violently in water; occurs in carnallite and lepidolite and pollucite

Other synonyms of Rb include rubidium.

Rb (noun)	atomic number 37 (noun)
a soft silvery metallic element of the alkali metal group; burns in air and reacts violently in water; occurs in carnallite and lepidolite and pollucite	a soft silvery metallic element of the alkali metal group; burns in air and reacts violently in water; occurs in carnallite and lepidolite and pollucite