Here's why:

* Sodium (Na) is a metal and has a tendency to lose one electron to achieve a stable electron configuration. This creates a positively charged sodium ion (Na+).

* Chlorine (Cl) is a nonmetal and has a tendency to gain one electron to achieve a stable electron configuration. This creates a negatively charged chloride ion (Cl-).

* The strong electrostatic attraction between the positively charged sodium ion and the negatively charged chloride ion forms an ionic bond, resulting in the formation of sodium chloride (NaCl), also known as table salt.