Here's the breakdown of protons, electrons, and neutrons in potassium:

* Protons: 19

* Electrons: 19 (in a neutral atom)

* Neutrons: 20 (for the most common isotope, potassium-39)

Explanation:

* Atomic Number: The atomic number of an element defines the number of protons in its nucleus. Potassium's atomic number is 19, meaning it has 19 protons.

* Electrons: In a neutral atom, the number of electrons always equals the number of protons. So, potassium also has 19 electrons.

* Neutrons: The number of neutrons can vary slightly within an element, creating isotopes. The most common isotope of potassium is potassium-39, which has 20 neutrons (39 - 19 = 20).

Key Points:

* Isotopes: Atoms of the same element with different numbers of neutrons are called isotopes.

* Mass Number: The mass number is the sum of protons and neutrons in an atom's nucleus.