Covalent Bond
Definition and meaning of Covalent Bond in chemistry.
A covalent bond is a chemical bond formed when two atoms share one or more pairs of valence electrons, most commonly between nonmetal atoms of similar electronegativity.
In more detail
By sharing electrons, each atom moves toward a more stable, often noble-gas-like electron configuration (the octet rule), lowering the overall energy of the system compared to the separate atoms. Covalent bonds are classified as single, double, or triple depending on how many electron pairs are shared; more shared pairs mean a shorter, stronger bond. Bonds can also be nonpolar (electrons shared equally) or polar (electrons shared unequally due to an electronegativity difference), which affects a molecule's overall polarity and reactivity.
Key facts
| Field | General Chemistry |
|---|---|
| Bond Types | Single, double, triple (increasing bond order) |
| Polarity Range | Nonpolar (ΔEN < ~0.4) to polar covalent (ΔEN ~0.4–1.7) |
| Typical Bond Energy | ~150–1000 kJ/mol, depending on bond order |
In methane (CH4), the carbon atom forms four single covalent bonds by sharing one electron pair with each of four hydrogen atoms, giving carbon a stable octet and each hydrogen a filled duplet.
Frequently asked questions
How is a covalent bond different from an ionic bond?
A covalent bond involves atoms sharing electron pairs, typically between elements with similar electronegativities, while an ionic bond forms when electrons are transferred completely, producing oppositely charged ions held together by electrostatic attraction.
Can a covalent bond involve more than one shared electron pair?
Yes; a double bond shares two electron pairs and a triple bond shares three, making the bond progressively shorter and stronger, as seen in O2 (double bond) and N2 (triple bond).