OCR A-level Chemistry A 2.2.1-2.2.2 Definitions

-Electron structure -Ionic bonding and structure -Covalent bonding -Shapes of molecules and ions -Electronegativity and polarity -Intermolecular forces -Hydrogen bonding

Orbital

A region of space around the nucleus that can hold up to two electrons, with opposite spins

Metallic bond

The attraction between a lattice of metal cations and delocalised outer shell electrons

Ionic bond

An electrostatic attraction between ions of opposite charge

Covalent bond

A shared pair of electrons between two nuclei

Molecule

A small unit of two or more atoms covalently bonded together

Double covalent bond

Two shared pairs of electrons between two nuclei

Triple covalent bond

Three shared pairs of electrons between two nuclei

Lone pair

A pair of electrons that is not involved with bonding

Dative covalent bond

A shared pair of electrons in which both bonded electrons are contributed by one of the atoms in the bond

Electronegativity

The ablility of an atom to attract the bonding pair of electrons in a covalent bond

Polar bond

A covalent bond between atoms with different electronegativities with positive and negative partial charges on the bonded atoms

Dipole

Positive and negative partial charges separated by a short distance in a molecule

Intermolecular forces

The weak attractive forces between molecules