What do Cl-35 and Cl-36 have in common?

they have same atomic number as they are the same element & electrons

they both have the atomic (proton number) as they are the same element hence they also they have the same number of electrons. Therefore they have similar chemical properties, as the electrons determine the chemical property of an element.

Explanation: The numbers 35 and 37 are the mass numbers for the two isotopes of chlorine. They both have the same atomic number (proton number ) as they are the same

if you're asking what comes out, it's steam.