Bond
Definition and meaning of Bond in chemistry.
A bond, or chemical bond, is the attractive force that holds two or more atoms together to form a molecule, ion, or extended solid, arising from the electrostatic interaction between nuclei and shared or transferred electrons.
In more detail
Bonds form because atoms lower their overall potential energy by rearranging valence electrons: in covalent bonds atoms share electron pairs, in ionic bonds electrons transfer to create oppositely charged ions that attract, and in metallic bonds electrons delocalize across a lattice of cations. The type and strength of a bond determine a substance's melting point, hardness, solubility, and reactivity. Bond order, length, and polarity (from electronegativity differences) are used to predict and explain molecular structure and behavior.
Key facts
| Field | General Chemistry |
|---|---|
| Main types | Covalent, ionic, metallic |
| Key properties | Bond length, bond energy, bond order, polarity |
| Example bond | H–H single bond, ~436 kJ/mol |
In a hydrogen molecule (H2), two hydrogen atoms each contribute one electron to a shared pair, forming a single covalent bond that holds the atoms together at an equilibrium distance of about 74 picometers.
Frequently asked questions
What is the difference between an ionic and a covalent bond?
Ionic bonds form through electrostatic attraction between oppositely charged ions created by electron transfer (typically between a metal and nonmetal), while covalent bonds form when atoms share electron pairs (typically between nonmetals).
What determines bond strength?
Bond strength depends mainly on bond order (single, double, triple), the atoms' sizes, and orbital overlap; shorter, higher-order bonds are generally stronger and require more energy to break.