What is the isotope's charge for potassium 39?
0 is the charge of the isotope because it has 19 electrons and 19 protons but 20 neutrons. Even if the number of neutrons changes it has no effect on the charge of the atom so 19- and 19+ leads to a neutral or no charge. 0 is the answer
The nomenclature "potassium-19" is not commonly used because it is redundant. The 19 in potassium-19 would indicate the number of protons in potassium. All isotopes of potassium have 19 protons. Therefore 19 is known as the atomic number of potassium. Potassium-41 is one of the three naturally occurring isotopes of potassium. It has 19 protons and 22 neutrons, giving it an atomic mass number of 41.
The mass number, the number that follows the hyphen at the end of an element name, is the sum of the atomic number of the element and the number of neutrons in each atom of the isotope specified by mass number. The atomic number of potassium is 19; therefore, potassium-39 contains (39 - 19) or 20 neutrons.