Answer:
Cl-
Step-by-step explanation:
When chlorine reacts with other substances, it usually forms the chloride ion (Cl-). This is because it has seven valence electrons, and in order to gain a full octet, it has to gain one electron (which has a negative charge). For example, when it reacts with Sodium (Na), the product is table salt (NaCl) because chlorine takes one electron from sodium and becomes Cl-. Sodium also becomes Na+, because it loses one electron.