Chemical Bonds and Their Properties

Chemical Bond

An attraction between atoms that allows the formation of chemical substances.

Bond Formation

Atoms form bonds to lower their potential energy and become more stable.

Attractive Forces

Forces such as electron-nucleus attraction that favor bond formation.

Repulsive Forces

Forces like nucleus-nucleus or electron-electron repulsion that oppose bond formation.

Lewis Dot Structure

A diagram showing the valence electrons around atoms and how they are involved in bonding.

Ionic Bond

A chemical bond formed by the transfer of electrons from a metal to a nonmetal, creating positive and negative ions.

Covalent Bond

A bond formed when two atoms share one or more pairs of electrons.

Network Covalent Bond

A type of bonding where atoms are continuously bonded in a large lattice, giving substances like diamond their strength.

Metallic Bond

A bond formed by the attraction between a lattice of metal cations and a "sea" of delocalized valence electrons.

Electronegativity

A measure of how strongly an atom attracts shared electrons in a bond.

Bond Polarity

A description of how equally or unequally electrons are shared in a covalent bond, based on electronegativity differences.

Octet Rule

Atoms tend to gain, lose, or share electrons to have eight electrons in their valence shell.

Ionization Energy

The energy required to remove an electron from an atom in its gaseous state.

Electron Shielding

The effect of inner electrons reducing the effective nuclear pull on outer electrons.

Electron-Deficient Molecule

A molecule in which an atom has fewer than eight electrons around it (e.g., BF₃).

Radical

A molecule or atom with an unpaired electron, often highly reactive.

Expanded Octet

A situation where atoms (typically in period 3 or below) have more than eight electrons around them, often using d orbitals.

Coordinate Covalent Bond

A covalent bond in which both electrons come from the same atom.

Atomic Orbital

A region of space where an electron is likely to be found, associated with individual atoms.

Hybrid Orbital

A mixed orbital formed from the combination of atomic orbitals to explain molecular geometry.

Molecular Geometry

The three-dimensional arrangement of atoms in a molecule.

Polarity of Molecule

The overall distribution of charge across a molecule, determined by both bond polarity and molecular shape.

Cis/Trans Isomers

Molecules with the same formula but different spatial arrangements around a double bond.

Saturated Molecule

A molecule containing only single bonds between carbon atoms.

Unsaturated Molecule

A molecule containing one or more double or triple carbon-carbon bonds.

Polyunsaturated Molecule

A molecule with more than one double or triple bond.

Sigma (σ) Bond

A single covalent bond formed by the head-on overlap of atomic orbitals.

Pi (π) Bond

A bond formed by the side-by-side overlap of p orbitals, found in double and triple bonds.

Double Bond

A covalent bond consisting of one sigma bond and one pi bond.

Triple Bond

A covalent bond made of one sigma bond and two pi bonds.

Resonance Structure

One of two or more valid Lewis structures for a molecule that differ only in the placement of electrons.

Bond Order

The number of chemical bonds between a pair of atoms; can be fractional when considering resonance.

Delocalized Electrons

Electrons that are not associated with a single atom or bond, often found in metallic and resonance systems.

Allotrope

Different forms of the same element with different bonding arrangements (e.g., diamond and graphite for carbon).

Malleability

The ability of a substance, particularly metals, to be hammered or rolled into sheets.

Ductility

The ability of a material to be drawn into wires.

Conductivity

The ability of a substance to conduct electricity, often due to mobile charge carriers like electrons.

Melting/Boiling Point (mp/bp)

The temperatures at which a substance changes from solid to liquid or liquid to gas; influenced by bond strength.