A Level Chemistry Definitions Papers 1 , 2 & 3 Papers 1 & 3 Papers
Mass Number Number of protons and neutrons
Change in c
Atomic Number Number of protons Rate of Reaction
ti
3.1.1 Atomic
Atoms with the same number of protons, Activation Energy The minimum energy for a re
Structure Isotopes
but a different number of neutrons 3.1.5 Kinetics
A substance that speeds up th
Energy required to remove an electron from a Catalyst
1st Ionisation Energy but it is not used up
gaseous atom. provides an alternative route
How a Catalyst Works
that has a lower activation en
average mass of one atom of an element
Relative Atomic Mass Forward rate = backward rate
1/12th mass of an atom of 12C 3.1.6 Chemical Dynamic Equilibrium Concentrations remain consta
Equilibria…
Relative Molecular average mass of an entity Le Chatelier’s Principle equilibrium will shift to oppo
3.1.2 Amount Mass Oxidation Loss of electrons
1/12th mass of an atom of 12C
of Substance Reduction Gain of electrons
1 Mole Avogadro’s number of particles 3.1.7 Redox
Oxidising Agent A species that gains electrons
Empirical Formula simplest ratio of atoms of each element in a compound Reducing Agent A species that loses electrons
Same molecular formula,
Structural Isomer
Molecular Formula Actual number of atoms of each element in a compound different structural formula
Same molecular formula,
The power of an atom to attract the pair of electrons Chain Isomer
Electronegativity different length carbon chain
from a covalent bond
Same molecular formula,
Covalent Bond shared pair of electrons 3.3.1 & 3.3.2 Position Isomer the functional group is on a d
a covalent bond Organic and chain
Co-ordinate Bond
3.1.3 Bonding in which both electrons are donated by one atom Alkanes Functional Group Same molecular formula,
Strong electrostatic attraction between oppositely Isomer different functional group
Ionic Bond
charged ions Saturated Contains only single bonds
Strong electrostatic attraction between positive ions Unsaturated Contains a C=C double bond
Metallic Bond Hydrocarbon Contains Hydrogen and Carbo
and delocalised electrons.
Fraction A mixture of compounds with
Enthalpy Change Heat change at constant pressure Nucleophile Electron pair donor
The enthalpy change when 1 mol of a substance Electrophile Electron pair acceptor
Enthalpy of Is completely burned in oxygen Addition 2 species makes 1 species
Combustion Under standard conditions, all substances in standard 3.3.3 – 3.3.5 Substitution 1 species is replaced with ano
states Haloalkanes / swapped)
The enthalpy change when 1 mol of a compound Alkenes / Hydration The addition of water
Mass Number Number of protons and neutrons
Change in c
Atomic Number Number of protons Rate of Reaction
ti
3.1.1 Atomic
Atoms with the same number of protons, Activation Energy The minimum energy for a re
Structure Isotopes
but a different number of neutrons 3.1.5 Kinetics
A substance that speeds up th
Energy required to remove an electron from a Catalyst
1st Ionisation Energy but it is not used up
gaseous atom. provides an alternative route
How a Catalyst Works
that has a lower activation en
average mass of one atom of an element
Relative Atomic Mass Forward rate = backward rate
1/12th mass of an atom of 12C 3.1.6 Chemical Dynamic Equilibrium Concentrations remain consta
Equilibria…
Relative Molecular average mass of an entity Le Chatelier’s Principle equilibrium will shift to oppo
3.1.2 Amount Mass Oxidation Loss of electrons
1/12th mass of an atom of 12C
of Substance Reduction Gain of electrons
1 Mole Avogadro’s number of particles 3.1.7 Redox
Oxidising Agent A species that gains electrons
Empirical Formula simplest ratio of atoms of each element in a compound Reducing Agent A species that loses electrons
Same molecular formula,
Structural Isomer
Molecular Formula Actual number of atoms of each element in a compound different structural formula
Same molecular formula,
The power of an atom to attract the pair of electrons Chain Isomer
Electronegativity different length carbon chain
from a covalent bond
Same molecular formula,
Covalent Bond shared pair of electrons 3.3.1 & 3.3.2 Position Isomer the functional group is on a d
a covalent bond Organic and chain
Co-ordinate Bond
3.1.3 Bonding in which both electrons are donated by one atom Alkanes Functional Group Same molecular formula,
Strong electrostatic attraction between oppositely Isomer different functional group
Ionic Bond
charged ions Saturated Contains only single bonds
Strong electrostatic attraction between positive ions Unsaturated Contains a C=C double bond
Metallic Bond Hydrocarbon Contains Hydrogen and Carbo
and delocalised electrons.
Fraction A mixture of compounds with
Enthalpy Change Heat change at constant pressure Nucleophile Electron pair donor
The enthalpy change when 1 mol of a substance Electrophile Electron pair acceptor
Enthalpy of Is completely burned in oxygen Addition 2 species makes 1 species
Combustion Under standard conditions, all substances in standard 3.3.3 – 3.3.5 Substitution 1 species is replaced with ano
states Haloalkanes / swapped)
The enthalpy change when 1 mol of a compound Alkenes / Hydration The addition of water
