Isotopes of Chlorine are variants of the chlorine atom that have the same number of protons but different numbers of neutrons. The two most common isotopes are Chlorine-35 and Chlorine-37. Chlorine-35 has 17 protons and 18 neutrons, while Chlorine-37 has 17 protons and 20 neutrons. These isotopes are stable and do not undergo radioactive decay. They are used in various applications, including water treatment and chemical synthesis. The natural abundance of Chlorine-35 is about 75.76%, while Chlorine-37 makes up about 24.24% of naturally occurring chlorine.