Structural isomers
Structural isomers are molecules with the same molecular formula but with different structural arrangements of atoms.
Stereoisomers
Stereoisomers are compounds with the same structural formula, but with a different arrangement of atoms in space.
E/Z isomerism
E/Z isomerism is a type of isomerism in which different groups attached to each carbon of a C=C double bond may be arranged differently in space because of the restricted rotation of the C=C bonds.
cis-trans isomerism
cis-trans isomerism is a special type of E/Z isomerism in which there is a non-hydrogen group and hydrogen on each C of a C=C double bond: the cis isomer(Z isomer) has the H atoms on each carbon on the same side; the trans isomer( E isomer) has the H atoms on each carbon on different sides.
Homolytic fission
Homolytic fission is the breaking of a covalent bond, with one of the bonded electrons going to each atom, forming two radicals.
Radical
Radical is a species with an unpaired electron.
Heterolytic fission
Heterolytic fission is the breaking of a covalent bond with both of the bonded electrons going to one of the atoms, forming a cation and an anion.
Nucleophile
Nucleophile is an atom(or group of atoms) that is attracted to an electron-deficient centre or atom, where it donates a pair of electrons to form a new covalent bond.
Electrophile
An electrophile is an atom(or group) that is attracted to an electron-rich centre or atom, where it accepts a pair of electrons to form a new covalent bond.
Addition reaction
An addition reaction is a reaction in which a reactant is added to an unsaturated molecule to make saturated molecule.
Substitution reaction
A substitution reaction is a reaction in which an atom or group of atoms is replaced with a different atom or group of atoms.
Elimination reaction
An elimination reaction refers to the removal of a molecule from a saturated molecule to make a unsaturated molecule.
radical substitution
Radical substitution is a type of substitution reaction in which a radical replaces a different atom or group of atoms.
Mechanism
Mechanism is a sequence of steps showing the path taken by electrons in a reaction.
Initiation
Initiation is the first step in a radical substitution in which the free radicals are generated by ultraviolet light.
Propagation
Propagation is the two repeated steps in radical substitution that build up the products in a chain reaction.
Termination
Termination is the step at the end of a radical substitution when two radicals combine to form a molecule.
Pi-bond
A pi-bond is the reactive part of a double bond formed above and below the plane of the bonded atoms by sideways overlap of p-orbitals.
Electrophilic addition
Electrophilic addition is a type of addition reaction in which an electrophile is attracted to an electron-rich centre or atom,where it accepts a pair of electrons to form a new covalent bond.
Carbocation
Carbocation is an organic ion in which a carbon atom has a positive charge.
Curly arrow
A curly arrow is a symbol used in reaction mechanisms to show the movement of an electron pair in the breaking or formation of a covalent bond.
