Question

All atoms of the element potassium have 19 protons. One of the most stable types of potassium atoms has the mass number 39.

Answer 1

20 neutrons is the correct answer

Step-by-step explanation:

I took the test I got the right answer.

Answer 2

The correct answer for the given question is 20 neutrons.

Step-by-step explanation:

As we know most of the elements have their isotopes present so the metal in the periodic table that has atomic number 19 and is named potassium has two stable isotopes.

One of the stable isotope is 39 and the other one is 41. The isotope of potassium that has atomic number 39 has the same number of Electrons and protons number of neutrons present in this isotope is 20.