Show science like law has own bureau of missing persons hunt Is on now for long lost parents of actinium rochester N Y the police may have their missing persons bureaus who hunt for the charley rosses bosses and judge craters of the world but science too has similar my mysteries and none so famous as the missing parents of the element actinium in a report to the american physical society prof T R wilkins and dr W M rayton of the university of rochester present new evidence which helps make clearer the ori origins of the missing long lived parents of the actinium series of radio elements how lost are traced scientific happenings which make it possible to throw light on the atomic missing persons problem are that sometimes the change from one element to another is is accompanied by a loss of weight and sometimes merely by a loss of electrical charge without the weight loss the loss of weight occurs when the nucleus of a helium atom known as an alpha particle is liberated in the radioactive disintegration then the parent atom drops drop s down dawn two whole numbers in th the e numerical scale which rates chemical element from hydrogen at one to uranium at 92 when electricity is given off by the emission of an electron the atomic number cumber of the element jumps back up the scale by one unit thus uranium 1 I 92 gives off an alpha particle and becomes uranium xi SO 90 but uranium X gives 0 off ff an electron and becomes uranium xi with atomic number 91 radium best known thus in stepwise fashion but sometimes up and sometimes down the scale of atomic numbers go the disintegrations of the heavy radioactive elements of which the best known is perhaps radium with atomic number 88 83 common gray and soft lead are the final offspring of all these spontaneous changes and there are four different kinds of lead radium lead thorium thorburn urn lead actinium lead and just lead the radium thorium and actinium here mean that it is lead which had each of these specific origins plain lead merely means that scientists cannot specifically civically fix its origin the ability of the radioactive atoms to lose or take on weight at various stages means that there will frequently be two or more varieties all having the same chemical properties but slightly different masses even though they may have the same atomic number rating thus uranium xi and its three isotopes as they are known all have atomic weight of one has an atomic number of 90 another is number 92 and two are number 91 while chemical methods are not nol sufficiently exact to permit distinguishing gui shing between all these varieties other methods and in particular the range with which alpha particles are emitted serve as experimental checks drs wilkins and rayton have studied the alpha particle ranges as their method in seeking lost parent the investigation also throws much needed light on the way alpha particles are emitted from the nucleus of atoms a problem which has bearing on the much studied and important field of the constitution of the inner cores ol of atoms details of the methods used will interest scientists but need not necessarily essa rily be presented for the layman suffice it to say that a bously unfound isotope of uranium has been indicated at least tentatively which might well serve as the parent for the now orphaned series of actinium radio elements |