Here's why:
* Ionic bonding: Sodium chloride forms through ionic bonding. Sodium atoms lose an electron to become positively charged sodium ions (Na+). Chlorine atoms gain an electron to become negatively charged chloride ions (Cl-).
* Electrostatic attraction: The opposite charges attract, forming a strong electrostatic bond.
* Crystal lattice: The ions arrange themselves in a repeating, three-dimensional structure called a crystal lattice. This lattice ensures a 1:1 ratio of sodium ions to chloride ions to maintain electrical neutrality.
Therefore, for every sodium ion in a salt crystal, there's one chloride ion, making them equal in number.
