When calcium and chlorine react to form an electron dot structure, calcium loses two electrons to chlorine, resulting in the formation of Ca2+ and Cl- ions.

The electron dot structure of calcium (Ca) shows two valence electrons in its outermost shell, represented as two dots or crosses:

Ca: 2e-

Chlorine (Cl) has seven valence electrons in its outermost shell, which it needs to gain one more electron to achieve a stable configuration. Its electron dot structure is:

Cl: 7e- + 1e- = 8e- (or Cl)

When calcium and chlorine react, calcium donates its two valence electrons to chlorine, forming ionic bonds. The resulting electron dot structures are:

Ca2+: 0e-

Cl-: 8e-

In this electron dot structure, calcium loses its two outermost electrons, resulting in a positive charge (2+). Chlorine gains two electrons to complete its outermost shell, resulting in a negative charge (1-). The attraction between these oppositely charged ions holds the compound together.