potassium39

Potassium-39, symbol 39K, is the most abundant stable isotope of the element potassium (Z = 19). It has 19 protons and 20 neutrons, giving a mass number of 39. It is stable and non-radioactive, with no known radioactive decay.

In natural potassium, 39K accounts for about 93.3% of all potassium atoms, with smaller amounts of 41K (~6.7%) and trace 40K (~0.012%). Because all isotopes of an element share the same chemical properties, 39K behaves chemically like potassium metal and its salts.

Occurrence and uses: 39K occurs in minerals such as feldspars and micas and is present in seawater and biological tissues. It is widely used in scientific analyses and instrumentation; its high natural abundance makes it common as a reference or calibrant in isotope ratio measurements and as a probe in nuclear magnetic resonance experiments for studying potassium environments in molecules and materials.

Note: Potassium is essential for life, playing roles in nerve signaling and fluid balance. The biological and environmental behavior of potassium is governed by overall chemistry rather than by individual isotope differences. Potassium-40 is a naturally occurring radioisotope that contributes to radiometric dating and environmental radioactivity, but 39K itself remains stable.