In , Antoine Becquerel discovered that a uranium-rich rock emits invisible rays that can darken a photographic plate in an enclosed container. Scientists offer three arguments for the nuclear origin of these rays. First, the effects of the radiation do not vary with chemical state; that is, whether the emitting material is in the form of an element or compound. Second, the radiation does not vary with changes in temperature or pressure—both factors that in sufficient degree can affect electrons in an atom. Third, the very large energy of the invisible rays up to hundreds of eV is not consistent with atomic electron transitions only a few eV. Today, this radiation is explained by the conversion of mass into energy deep within the nucleus of an atom.
Isotopes of uranium
What is Uranium-lead Dating - Definition
By Griffon , December 29, in Physics. I've been poking about on the internet again as you do and found a whole load of stuff by creationists about the problems with carbon 14 radiometric dating. Specifically they report with some glee that coal has been found to contain measurable amounts of carbon14 which it should not of course because it is about million years old and dates from the carboniferous period. C14 has a half life of years and is only good to date objects to 50, years or so.
Carbon has a large number of stable isotopes. All carbon atoms contain six protons and six electrons, but the different isotopes have different numbers of neutrons. The amount of carbon in the atmosphere has not changed in thousands of years.
Klaproth recognized an unknown element in pitchblende and attempted to isolate the metal in The metal apparently was first isolated in by Peligot, who reduced the anhydrous chloride with potassium. Sources Uranium, not as rare as once thought, is now considered to be more plentiful than mercury, antimony, silver, or cadmium, and is about as abundant as molybdenum or arsenic. It occurs in numerous minerals such as pitchblende, uraninite, carnotite, autunite, uranophane, and tobernite. It is also found in phosphate rock, lignite, monazite sands, and can be recovered commercially from these sources.