At vs astatine

At and astatine both are nouns.

Word	Noun	Adjective	Verb	Adverb
At	Yes	No	No	No
astatine	Yes	No	No	No

As nouns, At and astatine are synonyms defined as:

At and astatine: a highly unstable radioactive element (the heaviest of the halogen series); a decay product of uranium and thorium

Other synonyms of At include atomic number 85.

At (noun)	astatine (noun)
a highly unstable radioactive element (the heaviest of the halogen series); a decay product of uranium and thorium	a highly unstable radioactive element (the heaviest of the halogen series); a decay product of uranium and thorium