Ionic Bonding
Definition and meaning of Ionic Bonding in chemistry.
Ionic bonding is the electrostatic attraction between oppositely charged ions that forms when one atom transfers one or more electrons to another. It typically occurs between a metal (which loses electrons to form a cation) and a nonmetal (which gains electrons to form an anion).
In more detail
The transfer happens because the large electronegativity difference between the two atoms makes it energetically favorable for one to give up electrons entirely rather than share them. The resulting cations and anions do not pair off individually; instead, they pack into an extended three-dimensional crystal lattice where each ion is surrounded by oppositely charged neighbors, maximizing attraction and minimizing repulsion. This lattice arrangement explains why ionic compounds are typically hard, brittle solids with high melting points, and why they conduct electricity only when molten or dissolved in water, since the ions must be free to move.
Key facts
| Field | General Chemistry |
|---|---|
| Classic example | NaCl (sodium chloride) |
| Typical bond type | Metal + nonmetal |
| Electronegativity difference | Usually greater than about 1.7 (Pauling scale) |
In sodium chloride, each sodium atom transfers its single valence electron to a chlorine atom, forming Na+ and Cl- ions. These ions arrange into a repeating cubic lattice held together by ionic bonds, producing table salt.
Frequently asked questions
How does ionic bonding differ from covalent bonding?
In ionic bonding, electrons are transferred completely from one atom to another, creating charged ions held together by electrostatic attraction. In covalent bonding, atoms share electron pairs instead of transferring them.
Why do ionic compounds have high melting points?
Because every ion in the crystal lattice is strongly attracted to several oppositely charged neighbors at once, a large amount of energy is needed to break apart the entire structure.