Here's how to determine the number of protons and electrons in a potassium atom:

* Protons: The number of protons in an atom defines its atomic number. Potassium (K) has an atomic number of 19. Therefore, a potassium atom has 19 protons.

* Electrons: In a neutral atom, the number of protons and electrons is equal. So, a potassium atom also has 19 electrons.