Chemical Bond
Definition and meaning of Chemical Bond in chemistry.
A chemical bond is the attractive force that holds two or more atoms together in a molecule, ion, or crystal, arising from the electrostatic interaction between nuclei and electrons.
In more detail
Bonds form because the resulting arrangement of nuclei and electrons has lower potential energy than the separated atoms, often (though not always) allowing atoms to attain a filled valence shell. The three main types are ionic bonds, formed by electron transfer between atoms of very different electronegativity to give attracting cations and anions; covalent bonds, formed by one or more shared electron pairs between atoms of similar electronegativity; and metallic bonds, where a lattice of metal cations is held together by a surrounding "sea" of delocalized electrons. Bond type and strength govern a substance's melting point, conductivity, solubility, and reactivity, and bond energies (typically 150-1000 kJ/mol for single covalent bonds) determine how much energy a reaction releases or absorbs.
Key facts
| Field | General Chemistry |
|---|---|
| Main types | Ionic, covalent, metallic |
| Typical single covalent bond energy | 150-1000 kJ/mol |
| Key driver | Electronegativity difference between bonded atoms |
In sodium chloride (NaCl), each sodium atom transfers one electron to a chlorine atom, producing Na+ and Cl- ions that form an ionic bond held together by electrostatic attraction throughout the crystal lattice.
Frequently asked questions
What is the difference between ionic and covalent bonds?
Ionic bonds form through electron transfer between atoms of very different electronegativity, creating oppositely charged ions that attract each other; covalent bonds form through the sharing of electron pairs between atoms of similar electronegativity.
What determines the strength of a chemical bond?
Bond strength depends mainly on bond order (single, double, or triple), the size of the bonded atoms, and how effectively their orbitals overlap; shorter, higher-order bonds are generally stronger.