large/12904/worldswithinworlds_v1-3_1904_librivox_64kb_mp3/worldswithinworlds_01_asimov_64kb_150
large/12904/worldswithinworlds_v1-3_1904_librivox_64kb_mp3/worldswithinworlds_01_asimov_64kb
English
12904
Though all give off beta particles, radium B has a half life of 27 minutes, radium D one of 19 years, thorium B one of 11 hours, and actinium B one of 36 minutes. In 1913 Soddy called atoms that were in the same place in the list of elements, but which had different radioactive properties, "isotopes", from Greek words meaning "same place". THOUGH ALL GIVE OFF BATEER PARTICLES RADIUM B HAS A HALF LIFE OF TWENTY SEVEN MINUTES RADIUM D ONE OF NINETEEN YEARS THORIUM B ONE OF ELEVEN HOURS AND ACTINIUM B ONE OF THIRTY SIX MINUTES IN NINETEEN THIRTEEN SODDY CALLED ATOMS THAT WERE IN THE SAME PLACE IN THE LIST OF ELEMENTS BUT WHICH HAD DIFFERENT RADIOACTIVE PROPERTIES ISOTOPES FROM GREEK WORDS MEANING SAME PLACE
ing off beta particles as it did so, that half of any given quantity would have broken down in 24 days. Another way of saying this (which was introduced by Rutherford) was that the “half-life” of uranium X₁, is 24 days. Ordinary thorium, however, gives off alpha particles, not beta particles, and does so at such a slow rate, that its half-life is 14 billion years! Uranium X₁, and ordinary thorium were in the same place in the list of elements by chemical standards, and yet there was clearly something different about the two. Here is another case. In 1913 the British chemist Alexander Fleck (1889- ) studied “radium B” and “radium D”, the names given to two different kinds of atoms in the uranium radioactive series. He also studied “thorium B” in the thorium radioactive series and “actinium B” in the actinium radioactive series. All four are chemically the same as ordinary lead; all four are in the same place in the list of elements. Yet each is different from the radioactive standpoint. ID SO THAT HALF OF ANY GIVEN QUANTITY WOULD HAVE BROKEN DOWN IN TWENTY FOUR DAYS ANOTHER WAY OF SAYING THIS WHICH WAS INTRODUCED BY RUFFORD WAS THAT THE HALF LIFE OF URANIUM X ONE IS TWENTY FOUR DAYS ORDINARY THORIUM HOWEVER GIVES OFF ALPHA PARTICLES NOT BATTER PARTICLES AND DOES SO AT SUCH A SLOW RATE THAT ITS HALF LIFE IS FOURTEEN BILLION YEARS URANIUM EX ONE AND ORDINARY THORIUM WERE IN THE SAME PLACE IN THE LIST OF ELEMENTS BY CHEMICAL STANDARDS AND YET THERE WAS CLEARLY SOMETHING DIFFERENT ABOUT THE TWO HERE IS ANOTHER CASE IN NINETEEN THIRTEEN THE BRITISH CHEMIST ALEXANDER FLECK BORN EIGHTEEN EIGHTY NINE STUDIED RADIUM B AND RADIUM D THE NAMES GIVEN TO TWO DIFFERENT KINDS OF ATOMS IN THE URANIUM RADIOACTIVE SERIES HE ALSO STUDIED THORIUM B IN THEIR THORIUM RADIOACTIVE SERIES AND ACTINIUM B IN THE ACTINIUM RADIOACTIVE SERIES ALL FOUR ARE CHEMICALLY THE SAME AS ORDINARY LEAD ALL FOUR ARE IN THE SAME PLACE IN THE LIST OF ELEMENTS YET EACH IS DIFFERENT FROM THE RADIOACTIVE STANDPOINT
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