Ionic Bond
Definition
A bond formed when one atom gives electrons to another, creating oppositely charged ions that attract. It is the bond in table salt.
Technical definition
An ionic bond is the electrostatic attraction between oppositely charged ions formed by electron transfer, typically between a metal and a nonmetal with a large electronegativity difference (usually above 1.7). Ionic compounds form extended crystal lattices rather than discrete molecules.
Example
In NaCl, sodium donates an electron to chlorine. The resulting Na+ and Cl- ions lock into a crystal lattice: table salt.
Common confusion
Ionic bonding is rarely 100 percent ionic. Most ionic bonds have some covalent character, and bonding exists on a spectrum rather than in neat boxes.