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definitions

IB Chemistry S2.2 Definitions

This page contains our IB Chemistry definitions for S2.2. By learning each one of these definitions, you will fully cover the content for IB Chemistry 'Covalent bonding & forces'.

adduct

Two molecules bound together by a dative bond

allotrope

A crystalline form of a compound

coordinate covalent bond

A covalent bond formed when a single atom donates a shared pair of electrons. Also called dative covalent bond 

covalent bond

The electrostatic attraction of two nuclei to a shared pair of electrons

dipole-dipole forces

The attraction between oppositely charged dipoles of two polar molecules

electron domain

The number of bonding and non-bonding pairs of electrons

electronegativity

Relative measure of the attraction an atom has for a shared pair of electrons when covalently bonded to another atom

hydrogen bonding

A dipole-dipole force that occurs between compounds with a hydrogen atom, and a lone pair present on one of nitrogen, oxygen, or fluorine

instantaneous dipole

A dipole created by having a high concentration of electrons in a certain area at any point in time. Found in London dispersion forces 

intermolecular forces

The forces between molecules

Lewis structure

A visual representation of covalent compounds, showing all valence electrons as dots, lines or Xs

non-polar bond

A bond formed when there is an electronegativity difference of <0.5, leading to no poles being formed

polar bond

A bond formed when there is an electronegativity difference of 0.5-1.8, leading to one atom pulling electrons more towards itself to create a negative pole on its side and a positive pole on the other atom

resonance hybrids

A molecule that has more than one correct lewis structure

resultant polarity

The directional sum of polarity when a molecule has multiple polar bonds

valence shell

Outermost energy level of an atom 

VSEPR theory

Valence shell electron pair repulsion theory. Allows us to determine the correct 3D shape of a covalent compound