A chemical bond is an intramolecular force of attraction that holds together atoms in a molecule or compound. Atoms form bonds to achieve a more stable electron configuration, typically a full outer shell (the octet rule).

Ionic Bonding

Ionic bonds occur when one atom (usually a metal) transfers one or more valence electrons to another atom (usually a nonmetal). This creates oppositely charged ions (a positive cation and a negative anion) that are held together by electrostatic attraction. The result is an ionic compound, typically a crystalline solid.

Covalent Bonding

Covalent bonds form when two atoms (usually nonmetals) share one or more pairs of valence electrons. This sharing allows both atoms to achieve a stable electron configuration. Covalent bonds create discrete molecules. A shared pair can form a single bond, two pairs form a double bond, and three pairs form a triple bond.

Metallic Bonding

Metallic bonding occurs between metal atoms. The valence electrons are delocalized and form a 'sea' of electrons that surrounds a lattice of positive metal cations. This electron sea is mobile, which explains why metals are good conductors of electricity and heat, and why they are malleable and ductile.

Bonding Summary

Ionic bonding is the result of one atom donating an electron to another atom so that both atoms complete their octets.
Covalent bonding is the result of atoms that both need electrons, so they share electrons.
Metallic bonding is the result of collectively shared electrons.

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Lesson 7: Chemical Formulas and Bonding

Key TermsExpand to see a glossary of important terms from this lesson.

Lewis Symbols

Practice: Valence Electrons

The Octet Rule

Writing Chemical Formulas

Naming Chemical Compounds

Practice: Naming Ionic Compounds

Practice: Naming Acids

Practice: Naming Molecular Compounds

Intramolecular Forces

Types of Chemical Bonds

Drawing Lewis Structures