41. At least 32 nuclear isomers have also been characterized, ranging in atomic mass from 170 to 200. 42. Standard atomic weight is related to atomic mass by the abundance ranking of isotopes for each element. 43. Spontaneous fission is feasible over practical observation times only for atomic masses of 232 amu or more. 44. The atomic masses of naturally occurring isotopes of an element determine the atomic mass of the element. 45. The exact ratio you get for a singly charged species is the exact atomic mass for that atom. 46. In fact, gravimetric analysis was used to determine the atomic masses of many elements to six figure accuracy. 47. A total of 38 isotopes of iodine have been discovered, with atomic masses ranging from 108 to 145. 48. Bismuth has classically been considered to be the heaviest naturally occurring stable element, in terms of atomic mass . 49. This rule predicts the atomic mass of nuclides and isotopes with an error of at most 1 %. 50. Its atomic mass is 91.224.
