The isotope with 19 protons and 20 neutrons is known as Potassium-39 (K-39). This isotope of potassium has a mass number of 39, which is the sum of the number of protons (19) and neutrons (20) in the nucleus. Potassium is an essential element in biological systems and plays a critical role in various physiological processes.
To break it down further, the number of protons determines the element’s identity—in this case, potassium. The number of neutrons can vary among isotopes of the same element, leading to different isotopes such as K-39, K-40, and K-41. K-39 is stable and relatively abundant, making up about 93% of naturally occurring potassium.