An ionic bond is a type of chemical bond that occurs between atoms with significantly different electronegativities, resulting in the transfer of electrons from one atom to another. It typically forms between a metal atom (which tends to have a lower electronegativity) and a non-metal atom (which tends to have a higher electronegativity).
In an ionic bond, the metal atom loses one or more electrons to achieve a stable, positively charged ion called a cation, while the non-metal atom gains those electrons to form a stable, negatively charged ion called an anion. The resulting oppositely charged ions are held together by electrostatic attraction, creating an ionic bond.
For example, consider the formation of common table salt, sodium chloride (NaCl). Sodium (Na) is a metal with one valence electron, while chlorine (Cl) is a non-metal with seven valence electrons. Sodium readily donates its valence electron to chlorine, forming Na⁺ (cation) and Cl⁻ (anion). The resulting electrostatic attraction between Na⁺ and Cl⁻ ions forms an ionic bond, creating the ionic compound sodium chloride.
Ionic bonds are typically strong and have high melting and boiling points because of the strong electrostatic forces between the charged ions. They also tend to form crystalline structures, as the ions arrange themselves in a repeating pattern called a crystal lattice.
It's important to note that in an ionic compound, the individual ions retain their respective properties but are held together by the ionic bond. Ionic compounds often exhibit characteristic properties such as high solubility in water, good electrical conductivity in the molten or aqueous state (due to the movement of ions), and the ability to form crystals with distinct geometric shapes.