41. The mass number is the sum of the number of protons and neutrons in a nucleus. 42. Molybdenum isotopes with mass numbers 111 and up all have half-lives of approximately . 15 �s. 43. Pentecostals in mass numbers were given 20-25 year prison terms and many perished there, including Voronaev. 44. The mass number is a dimensionless quantity. 45. They have mass numbers of 217 242, 46. There are panoramic shots of the city that display the mass numbers of race participants and spectators. 47. Beta decay leaves the mass number unchanged, so that the change of nuclear spin must be an integer. 48. Radium has 33 known isotopes, with mass numbers from 202 to 234 : all of them are radioactive. 49. There are 19 isotopes of neptunium with mass numbers from 225 to 244; they are all highly radioactive. 50. The mass number of this isotope was not clearly established ( possibly 258 or 259 ) at the time.
