Chemistry: A Volatile History to investigate. Marie Curie began her investigations by testing a uranium ore called pitchblende with an electrometer. She discovered it was four times more radioactive than pure uranium, and wondered if this was due to the presence of an even more radioactive element in the pitchblende. Curie began stockpiling tonnes of pitchblende, then in the most basic of workshops with primitive equipment she undertook a multitude of complex and dangerous procedures in an attempt to isolate this new element. In the event, Curie discovered two new elements, polonium named after her native Poland and radium. Whilst these were naturally occurring
Isotopes of uranium Isotopes of uranium Uranium (U) is a naturally occurring radioactive element that has no stable isotopes but two primordial isotopes (uranium-238 and uranium-235) that have long half-lives and are found in appreciable quantity in the Earth's crust, along with the decay product uranium-234. The standard atomic weight of natural uranium is . Other isotopes such as uranium-232 have been produced in breeder reactors. Naturally occurring uranium is composed of three major isotopes, uranium-238 (99.2739–99.2752% natural abundance), uranium-235 (0.7198–0.7202%), and uranium-234 (0.0050–0.0059%). All three isotopes are radioactive, creating radioisotopes, with the most abundant and stable being uranium-238 with a half-life of