Radioactive element whose atomic number is 89 (8)
I believe the answer is:
actinium
(Another definition for actinium that I've seen is " Radioactive metallic element".)
I've seen this clue in The Independent.
Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free.
Check out my app
or
learn more
about the Crossword Genius project.