A recommendation letter or letter of recommendation, also known as a letter of reference, reference letter or simply reference, is a document in which the writer assesses the qualities, characteristics, and capabilities of the person being recommended in terms of that individual's ability to perform a particular task or function.
This article is about stable isotope ratios. For the general category of stable nuclides, see Stable nuclide. The term stable isotope has a similar meaning to stable nuclide, but is preferably used when speaking of nuclides of a specific element.his article is about stable isotope ratios. For the general category of stable nuclides, see Stable nuclide. The term stable isotope has a similar meaning to stable nuclide, but is preferably used when speaking of nuclides of a specific element.
Share. This is a list or table of elements that are radioactive. All elements have radioactive isotopes. This table contains the elements that have no stable isotopes.Each element is followed by the most stable known isotope and its half-life.This list is sorted by increasing atomic number.Reference: International Atomic Energy Agency ENSDF database (Oct 2010).his table contains the elements that have no stable isotopes. Each element is followed by the most stable known isotope and its half-life. This list is sorted by increasing atomic number. Reference: International Atomic Energy Agency ENSDF database (Oct 2010).