Why In News
The heaviest proton emitter, 188At (astatine), was recently identified and its half-life determined by a multinational team headed by scientists at the University of Jyväskylä in Finland.
Key Features
· Radioactivity:
o All 41 known isotopes are radioactive.
o Most stable isotope: Astatine-210 with a half-life of ~8.1 hours.
o Emits alpha and beta particles, ionizing surrounding air (blue glow).
· Physical State (probable):
o Believed to be a dark-colored solid at room temperature, but not confirmed due to its rarity.
· Chemical Behavior:
o Belongs to the halogen family (like F, Cl, Br, I).
o Chemically resembles iodine, but shows more metallic behavior.
o Likely forms astatides and reacts with metals.
Nuclear Decay Example
· Astatine-188 → emits proton → Polonium-187 (half-life ~1.4 ms)
· Polonium-187 → alpha decay → Lead-183, and so on → until a stable nucleus is formed.
Occurrence
· Natural Occurrence:
o Forms as a decay product of heavier radioactive elements (e.g., uranium, thorium).
· Synthetic Production:
o Can be produced in particle accelerators via bombardment reactions.
