Radium - Law Dictionary Search Results
Home Dictionary Name: radiumRadium
An intensely radioactive metallic element found combined in minute quantities in pitchblende and various other uranium minerals Symbol Ra atomic weight 2264 Radium was discovered by M and Mme Curie of Paris who in 1902 separated compounds of it by a tedious process from pitchblende Its compounds color flames carmine and give a characteristic spectrum It is divalent resembling barium chemically The main isotope of radium found in pitchblende radium 226 has a half life of 1620 years decaying first by alpha emission to radon...
Mesothorium
a radioactive isotope of radium radium 228 with a half life of 58 years Also called mesothorium 1 or mesothorium I to distinguish it from a subsequent decay product mesothorium II actinium 228 It was discovered in 1907 by Otto Hahn as a decay product of thorium produced by decay of thorium 232 Mesothorium 1 radium 228 in turn produces actinium 228 mesothorium 2 as the first product of its radioactive decay and the actinium 228 in turn decays quickly half life of 6 hours to thorium 228 which is also called radiothorium the thorium 228 has a half life of 191 years shorter than that of the radium 228 It was discovered and named before full recognition of the nature of isotopes of the elements and was distinguished from other variants of radium by its half life and mode of production and decay It was also cheaper to prepare than other short lived radium isotopes and was thus sold commercially for use eg in making watch dials readable in the dark by painting the hands and hour marks with a ...
Polonium
A radioactive chemical element discovered by M and MMe Curie in pitchblende and originally called radium F It has atomic number 84 and an atomic weight of 210 It is a very rare natural element having an abundance in uranium ores only 02 that of radium It is closely related chemically to bismuth It emits only alpha rays and has a half life of 138 days It is thus more unstable than radium and a milligram of polonium emits as many alpha particles as 5 grams of radium Twenty seven isotopes are known with atomic masses from 192 to 218 At present a more practical method of preparation than isolation from ores is the preparation by neutron bombardment of bismuth in a nuclear reactor and it may be obtained commercially by users having an appropriate permit...
Radon
An intensely radioactive gaseous element produced by the radioactive decay of radium 226 which is the main isotope of radium found in pitchblende Chemically it is an inert noble gas Its atomic symbol is Rn It has an atomic number of 86 The radon isotope produced by decay of radium has an atomic weight of 222017 and this isotope decays by alpha emission with a half life of 382 days Numerous other isotopes have been observed all radioactive and all having half lives shorter than that of radon 222 Radon was discovered by M and Mme Curie of Paris in their studies of the radioactive substances in pitchblende Radon was originally called radium emanation or exradio...
Beta rays
a form of ionizing radiation emitted by radioactive substances such as radium more penetrating than alpha rays and consisting of negatively charged electrons The electrons are the same kind of particle as those of cathode rays but have much higher velocities about 35000 to 180000 miles per second They are readily deflected by a magnetic or electric field...
Helium
An inert monoatomic gaseous element occurring in the atmosphere of the sun and stars and in small quantities in the earths atmosphere in several minerals and in certain mineral waters It is obtained from natural gas in industrial quantities Symbol He atomic number 2 at wt 40026 C12011 Helium was first detected spectroscopically in the sun by Lockyer in 1868 it was first prepared by Ramsay in 1895 Helium has a density of 198 compared with hydrogen and is more difficult to liquefy than the latter Chemically it is an inert noble gas belonging to the argon group and cannot be made to form compounds The helium nucleus is the charged particle which constitutes alpha rays and helium is therefore formed as a decomposition product of certain radioactive substances such as radium The normal helium nucleus has two protons and two neutrons but an isotope with only one neutron is also observed in atmospheric helium at an abundance of 0013 Liquid helium has a boiling point of 2689deg C at atmospheri...
radiothorium
an earlier name for the thorium isotope thorium 228 given by its discoverer Otto Hahn It is a radioactive substance formed as one of series of products in the chain of radioactive decay of thorium Its immediate predecessor in the chain is Actinium 228 and it decays by alpha emission to radium 224 with a half life of 191 years The name radiothorium was given prior to the full understanding of the nature of isotopes of elements...
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