One chemistry question, I am having a little trouble, please help!!?

[Mathew B]

A neutral atom of potassium has an atomic number of 19 and an atomic mass number of 39. Find its number of protons, neutrons and electrons.




thank you to all who answered!!

[Norrie]

The Atomic number refers to the number of Protons.
In a neutral atom, it also represents the number of electrons, (Equal (+) and (-) = Zero charge).
Potassium (K), with an Atomic mass of 39; 19 of which are Protons...we have 39 - 19 = 20 Neutrons.

(The At.mass of an atom is contained in the Nucleus only, (Protons + Neutrons).
Because their mass is about 1/1840th that of a Proton (or Neutron), Electrons are classed as insignificant mass).

[bsbdesja]

the atomic number represents the number of protons in the atom. If it is an atom and not an ion, this also represents the number of electrons in the atom.

Potassium has: 19 electrons
19 protons
20 neutrons

hope this helps.