Chlorine has two stable isotopes, which are: 1. **Chlorine-35 (¹⁷Cl)**: This isotope has 17 neutrons and is the more abundant of the two, making up about 76% of naturally occurring chlorine. 2. **Chlorine-37 (¹⁹Cl)**: This isotope has 20 neutrons and accounts for about 24% of natural chlorine.
