Here's why:
* Electrons lost: When an atom loses electrons, it becomes positively charged (a cation).
* Electrons gained: When an atom gains electrons, it becomes negatively charged (an anion).
* Electrostatic attraction: The opposite charges of the cation and anion attract each other, creating a strong electrostatic force that holds them together. This force is the ionic bond.
Example:
* Sodium (Na) has one valence electron. It tends to lose this electron to become a positively charged sodium ion (Na+).
* Chlorine (Cl) has seven valence electrons. It tends to gain one electron to become a negatively charged chloride ion (Cl-).
* The strong attraction between the positively charged sodium ion and the negatively charged chloride ion forms the ionic bond that creates sodium chloride (NaCl), or table salt.
