R1A1D2I1O1S1T1R1O1N1T1I1U1M3
17 points
RADIOSTRONTIUM is validvalid
a radioactive isotope of strontium, esp. strontium-90
a radioactive isotope of strontium, esp. strontium-90
a radioactive isotope of strontium, esp. strontium-90
a radioactive isotope of strontium, esp. strontium-90