Topic 1: Atomic structure
Element
A substance made of only one atom
Atomic proton
Total number of protons found in the nucleus of the atom mass of nucleon
number
number equal total number of protons and neutrons inside of the nucleus of an
atom
Nucleon number The total number of protons and neutrons in the nucleus of an atom
Isotopes
An atom of the same element with the same number of protons but different
number of neutrons
st
1 ionization
The energy needed to remove 1 mole of electrons from 1 mole of atoms of an
energy
element in the gaseous state to form 1 mole of gaseous ions
nd
2 ionization
As the energy needed to remove 1 mole of electrons from 1 mole of positively
energy
charged +1 cations of an element in the gaseous state to form 1 mole of positively
charge +2 cations of and element
Topic 2: atoms, molecules and stoichiometry
Unified atomic
One twelfth of the mass of a carbon-12 atom
mass
Relative atomic
The average mass of atoms of an element, taking into account the proportions of
mass
naturally occurring isotopes, compared to 1/12 of atom of carbon-12 isotope 12 C
Relative formula
mass
Relative isotopic
mass
Relative
molecular mass
Avogadro
constant
The ratio of the average mass of the atoms of an element to the unified atomic
mass
Mass of 1 formula unit of a compound compared to 1/12 of an atom of carbon 12 isotope, 12C
Mass of one particular isotope of an element compared to 1/12 of an atom of
carbon-12 isotope, 12C
The mass of a particular isotope of an element which has the Avogadro number of
atoms (6.02 x 1023 )
Mass of a molecule compared to 1/12 of an atom of carbon isotope, 12C
the ratio of the weighted average mass of a molecule of a molecular compound
to the unified mass unit
The no of particles (atoms, molecules, ion, electrons) in one mole of any
substance (6.02 x 1023)
Topic 3: chemical bonding
Electronegativity A measure of the tendency of an atom in a covalent bond to attract a bonding
pair electron
Bond energy
The energy required to break 1 mole of covalent bond between two atoms in the
gaseous state
Bond length
The distance between the nuclei of the two atoms joined by a covalent bond
Dative bond/
(covalent) bond with both electrons are provided from the same / one species\
coordinate bond OR
shared pair (of electrons) are provided from the same species / one atom owtt
Topic 4: States of matter
Ionic solids
It consists of positive and negative ions arranged alternatively in a crystal lattice
and are held together by strong electrostatic force of attraction.
Metallic solids
It consists of a lattice of a positive metal ions with the outer electrons forming
‘sea of delocalised electrons’
Malleable
Easily rolled into sheets or hammered into shapes
Ductile
Easily drawn into wires
Simple molecular It consists of a lattice of discrete molecules held together by weak intermolecular
solids
forces of attraction
Giant molecular
It consists of a lattice of atoms held together by strong covalent bonds
solids
Topic 5: chemical energetics
Exothermic
Release heat to the surrounding
reaction
Endothermic
Absorbs heat from the surrounding
reaction
Enthalpy change The change in heat energy content measured at standard pressure
Enthalpy change The enthalpy change when one mole of a substance is formed from its elements
of formation
under standard conditions
Enthalpy change As the enthalpy change when one mole of a substance completely burnt in
of combustion
excess oxygen under standard conditions
Enthalpy change The enthalpy change when one mole of a water is formed in the neutralization
of neutralization between an acid and an alkali, the reaction being carried out in aqueous solution
under standard conditions
Rate of reaction Change in amount of substance with time
Topic 6: electrochemistry
Redox reaction
A reaction in which the reduction of one reactant and the oxidation of another
reactant occurs
Oxidizing agent
Reactant that causes oxidation but itself reduced in the process
Reducing agent
Reactant that causes reduction but itself oxidise in the process
Oxidation
Loss of electrons
Reduction
Gain of electrons
Disproportionation The simultaneous oxidation and reduction of same species in one chemical
reactions
reaction
Topic 7: equilibria
Reversible
reaction
Kp
A chemical reaction which can proceed in both directions
Mole fraction of a
gas
Strong acids
The ratio of moles of a particular gas to the total number of moles of gas present
Equilibrium constant in terms of partial pressures
It completely dissociate in water to form H+ ions
Weak acids
Strong base
Weak base
Bronsted – lowry
acid
It partially dissociate in water to form H+ ions only few acid molecules will
ionised in water to give H+ ions most of the acid molecules remain unionised in
water
It completely dissociate in water to give OH+ ions
A substance that partially dissociate in water to give OH+ ions only few base
molecules will ionized in water to give OH+ ions most of the base molecules
remain unonised in water
A species which donates H+ to a base
Bronsted – lowry
bases
Conjugate base
A species which accepts protons H+ from an acid
Conjugate acid
This is the article formed when the base has accepted the proton
Ph scale
A numerical scale that shows how acidic and alkali a solution is
This is particle left when the acid has given away its proton
Topic 8: reaction kinetics
Rate of reaction
Change in concentrations of reactants and product per unit time
Effective collision
When particles collide in the correct orientation and enough energy for a
chemical reaction to take place
Activation energy The minimum amount of energy that reactant particles must possess in order to
react
Catalyst
A substance that which alters the rate of a reaction but is left chemically
unchanged at the end of the reaction
Homogeneous
A catalyst and the reactants in a catalysed reaction are in the same phase
catalyst
Heterogeneous
A catalyst that is in a different phase to the reactants
catalyst
Topic 9: the periodic table: chemical periodicity
Atomic radius
Half the distance between two covalently bonded atoms
Van der waals’
Half the distance between two atoms which are not chemically bonded
radius
Melting point
The temperature at which a pure solid is in equilibrium with its pure liquid at
atmospheric pressure
Topic 13 : Organic chemistry
Hydrocarbons
Compound that are made up of carbon and hydrogen atoms only
Functional group
An atom or group of atoms, when present in an organic molecule decides the
physical and chemical properties of that molecule
Empirical formula The simplest ration of the number of atoms of each element present in one
molecule of a compound
General formula
A formula that represent a homologous series of compounds using letter and
numbers
A group of organic compounds that have the same functional group, the same
general formula the same general formula and the same chemical properties
Molecular formula Gives the actual number of atoms of each element present in one molecule of a
compound
Structural formula Show how the constituent atoms of a molecule are joined together
Displayed formula Shows both the relative placing of atoms and the number of bonds between
them
Skeletal formula
Show the carbon skeleton only
Three dimension
Gives the best representation of the shape of a molecule
formula
Homolytic fission
The breaking of a covalent bond such that one electron goes to each of the
atom, forming free-radical
Heterolytic fission The breaking of a covalent bond such that both the electrons go to the same
atom, forming positive and negative ions
Alkane
Free radical
initiation
propagation
Termination
Nucleophiles
Electrophiles
Is an atom or group of atoms with an unpaired electron formed from the
homolytic fission of a covalent bond and are very reactive
The first step and involves the breaking of covalent bond using the energy from
ultraviolet light from the sun to form two free radicals
The second step in which the formed radical can attack reactant molecules to
form even more free radicals. These in turn can again attack other molecules to
form more free radicals and so on
Two free radicals react together to from a product molecule
Are species which contain a lone pair of electrons and are attracted to regions of
positive charge or electron-deficient sites in a molecule
Are electron deficient species which can accept electrons and are attracted to
regions of negative charge or electron rich
Types of reaction
Addition reaction
Substitution
reaction
Elimination
reaction
Hydrolysis
Condensation
reaction
Oxidation reaction
Reduction
reaction
Mechanism
Free-radical
substitution
reaction
Electrophilic
addition reaction
Nucleophilic
substitution
reaction
Nucleophilic
addition reaction
Involve two molecules joining together to form a single new molecule
Involves replacing an atom by another atom
Reaction in which a small molecule (such as H2O and HCl) has been lost
A chemical reaction in which water reacts with a compound to produce other
compounds. It involve the splitting of a bond and the addition of the hydrogen
cation and the hydroxide anion from water.
A reaction in which two organic molecules join together and involves eliminating
small molecules such as H2O or HCL
Is a reaction in which oxygen is added, electrons are removed or the oxidation
number of a substance is increased
A reaction in which oxygen is removed, electrons are added or the oxidation
number of a substance is decreased
A reaction in which halogen atoms substitute for hydrogen atoms in alkanes
A reaction in which an electron rich region in a molecule is attacked by an
electrophile followed by addition of a small molecule to give one product only
a reaction in which an electron-rich nucleophile displaces a halogen
A reaction in which a nucleophile attacks an electron deficient region in a
molecule followed by the addition of a small molecule to give one product only