* Electronegativity: Chlorine has a higher electronegativity than sulfur (3.16 vs 2.58). This means chlorine has a stronger attraction for electrons, making it more likely to gain electrons and form negative ions.

* Electron Affinity: Chlorine has a higher electron affinity than sulfur. This means chlorine releases more energy when it gains an electron, making it more favorable for chlorine to form negative ions.

* Ionization Energy: Chlorine has a higher ionization energy than sulfur. This means it requires more energy to remove an electron from a chlorine atom, making it less likely to lose electrons and form positive ions.

* Reactivity Trends: In general, elements become less reactive as you move down a group in the periodic table. Chlorine is higher up in Group 17 (halogens) than sulfur in Group 16 (chalcogens).

Overall: These factors contribute to chlorine being a more reactive element than sulfur. It readily forms negative ions and participates in a wider range of chemical reactions.