Answer: Radioactive element
Notes: A new scientific breakthrough was made when researchers from the University of Jyväskylä, Finland, successfully measured the half-life of the heaviest proton emitter isotope, 188At (Astatine). Astatine is a rare and highly radioactive element with atomic number 85, and it belongs to the halogen group in the periodic table. Unlike other halogens like fluorine and iodine, astatine has no stable isotopes. It is extremely radioactive, possibly appears as a dark solid, and emits a blue glow due to ionizing radiation. It occurs naturally as a decay product but has a very short half-life.
