IB HL Chemistry

IB Chemistry HL topic 1, 2, 3, 4, 12 and 13

atomic radius trend

increases down a group

Avogadro's number

6.02 x 10^23

Calculating relative atomic mass

(mass* %)+(mass*%)
-----------------------
100

Charge center

Lone pair or bond

Common ligands

H2O

Decomposition

bringing to its elemental form

dipole-dipole forces

attractions between oppositely charged regions of polar molecules

electromagnetic spectrum

All of the frequencies or wavelengths of electromagnetic radiation

Electronegativity

A measure of the ability of an atom in a chemical compound to attract electrons

Emprical Formula

gives ratio between the elements within the molecule

endothermic reaction

Ionisation energy

Gas --> liquid

condensation

Gas --> solid

deposition

Ionic lattice

- high melting and boiling point
- soluble
-conduct electricity when molten or in a solution because ions are free to move

Ionisation energy

Energy required to have an electron leave

Level 8/∞

after electron leaves the atom

Ligands

any molecule that binds specifically to a receptor site of another molecule

Liquid --> gas

evaporation

liquid --> solid

freezing

London dispersion forces

a temporary attractive force that results when the electrons in two adjacent atoms occupy positions that make the atoms form temporary dipoles

Molecular formula

indicates the direct number of elements present in the molecule

Orbital rules - Aufbua

Electrons fill atomic orbitals of lowest energy first

Orbital rules - Hund's

Electrons fill orbitals in the same sub level singly before pairing up

Orbital rules - Pauli

An atomic orbital can hold a maximum of 2 electrons

solid --> gas

sublimation

Solid --> liquid

melting

uncertainty principle

the position and the velocity of an object cannot both be measured exactly

van der Waals forces

intermolecular forces of attraction

Volatility

the tendency of a substance to vaporize