How many protons and neutrons are in cl-37

17 protons and 20 neutrons

Explanation:

Chlorine (Cl) is an element of the periodic table whose atomic number is 17 and enters the group of halogens.

Cl37 is a stable isotope (atom from an element with the same atomic number but different atomic mass) of chlorine.

Is an isotope of chlorine found in nature, representing ~24% of the total.