Conversation so far:
which is the correct way to write iodine (i) with an atomic mass of 131
Iodine-131 (131I, I-131) is a radioactive isotope of iodine with an atomic mass of 131.
who discovered iodine-131
Iodine-131 was discovered by Glenn Seaborg and John Livingood in 1938 at the University of California, Berkeley..

Question: what is the half-life
Self-contained rewrite: what is the half-life of iodine-131