High Quality Content by WIKIPEDIA articles! Potassium (K) has 25 known isotopes from 32K to 56K. Three isotopes occur naturally: stable 39K (93.3%) and 41K (6.7%), and the long-lived radioisotope 40K (0.012%). The standard atomic mass is 39.0983(1) u. Naturally occurring 40K decays to stable 40Ar (11.2% of decays) by electron capture or positron emission (giving it the longest known positron-emitter nuclide half-life). Alternately and most of the time (88.8%) it decays to stable 40Ca by beta decay; 40K has a half-life of 1.248?109 years. All other isotopes have half-lives under a day, most under a minute. The least stable are 33K and 34K, both with half-lives shorter than 25 nanoseconds. The half-life of 32K is unknown. Данное издание представляет собой компиляцию сведений, находящихся в свободном доступе в среде Интернет в целом, и в информационном сетевом ресурсе "Википедия" в частности. Собранная по частотным запросам указанной тематики, данная компиляция построена по принципу...