Here's why:
* Chlorine is a nonmetal and tends to gain an electron to form a negatively charged ion called a chloride ion (Cl-).
* Metals tend to lose electrons to form positively charged ions called cations.
When these two elements react, the metal loses electrons to the chlorine, forming an ionic bond between the positively charged metal cation and the negatively charged chloride anion. The resulting compound is called a metal chloride.
Examples:
* Sodium (Na) + Chlorine (Cl) → Sodium chloride (NaCl)
* Calcium (Ca) + Chlorine (Cl) → Calcium chloride (CaCl₂)
* Aluminum (Al) + Chlorine (Cl) → Aluminum chloride (AlCl₃)
