How many neutrons protons and electrons does potassium have.?
Use the Periodic Table to get Atomic number (19), and atomic mass (39.1). The atomic number is the number of protons, and in the neutral atom, also the number of electrons: 19. The atomic mass is the sum of the mass of the protons and neutrons, 39.1. Subtract the number of protons (use integers) from the atomic mass, 39 – 19 = 20, which is the number of neutrons.