To find out how many neutrons are in potassium, we first need to know the atomic number and the mass number (also known as atomic mass) of the specific isotope of potassium we’re interested in. Potassium has several isotopes, but the most stable ones are potassium-39, potassium-40, and potassium-41.
Potassium-39 (³⁹K): The atomic number of potassium is 19, which means it has 19 protons. The mass number of potassium-39 is 39. To find the number of neutrons, we subtract the atomic number from the mass number: 39 (mass number) - 19 (protons) = 20 neutrons.
Potassium-40 (⁴⁰K): This is a radioactive isotope of potassium. Using the same method: 40 (mass number) - 19 (protons) = 21 neutrons.
Potassium-41 (⁴¹K): Again, subtracting the atomic number from the mass number: 41 (mass number) - 19 (protons) = 22 neutrons.
So, the number of neutrons in potassium can be 20, 21, or 22, depending on whether you’re looking at the ³⁹K, ⁴⁰K, or ⁴¹K isotope, respectively. The most common and stable form, potassium-39, has 20 neutrons.
