Isotopes of berkelium
is an artificial element, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 243Bk in 1949. There are 18 known radioisotopes, from 233Bk to 253Bk, and 6 nuclear isomers. The longest-lived isotope is 247Bk with a half-life of 1,380 years.
