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When an organic reaction takes place, bonds in the reactant molecules are broken and bonds in the product molecules are made. The process of bond breaking is known as bond fission.

• results in the formation of two neutral radicals • occurs when each atom retains one electron from the sigma covalent bond and the bond breaks evenly • normally occurs when non-polar covalent bonds are broken • Requires UV to do so

• results in the formation of two oppositely charged ions • occurs when one atom retains both electrons from the sigma covalent bond and the bond breaks unevenly • normally occurs when polar covalent bonds are broken

two single-headed arrows starting at the middle of a covalent bond indicate homolytic bond fission is occurring

two double-headed arrow starting at the middle of a covalent bond indicates heterolytic bond fission is occurring

a double-headed arrow indicates the movement of an electron pair

a single-headed arrow indicates the movement of a single electron

• negatively charged ions or neutral molecules that are electron rich • attracted towards atoms bearing a partial positive or full positive charge • capable of donating an electron pair to form a new covalent bond

Chloride ion, bromide ion, hydroxide ion, cyanide ion, ammonium and water

• positively charged ions or neutral molecules that are electron deficient • attracted towards atoms bearing a partial or full negative charge • capable of accepting an electron pair to form a new covalent bond

In a skeletal structural formula, neither the carbon atoms, nor any hydrogens attached to the carbon atoms, are shown

Haloalkanes (alkyl halides) are substituted alkanes in which one or more of the hydrogen atoms is replaced with a halogen atom

• contain only one halogen atom • can be classified as primary, secondary or tertiary according to the number of alkyl groups attached to the carbon atom containing the halogen atom

• nucleophilic substitution reaction • one species in the rate determining step • occurs in a minimum of two steps • via a trigonal planar carbocation intermediate.

• nucleophilic substitution reaction • two species in the rate determining step • occurs in a single step • via a single five-centred, trigonal bipyramidal transition state

• ALKYL Positive inductive effect • Electron donating and push electrons towards the positive charge on the carbon which helps to stabilise it.

• The size of the alkyl groups causes the steric effect • In SN2 the nucleophile attacks from the side opposite the halogen • Tertiary haloalkanes resist this attack as it is sterically hindered as the three bulky alkyl groups prevent access to the positive carbon

Tertiary haloalkanes

Primary monohaloalkanes

Alcohols are substituted alkanes in which one or more of the hydrogen atoms is replaced with a hydroxyl functional group, –OH group.

Hydroxyl groups make alcohols polar, which gives rise to hydrogen bonding

• Ethers can be regarded as substituted alkanes in which a hydrogen atom is replaced with an alkoxy functional group, –OR, and have the general structure R’ – O – R’’, where R’ and R’’ are alkyl groups

Due to the lack of hydrogen bonding between ether molecules, they have lower boiling points than the corresponding isomeric alcohols

Ethers are named as substituted alkanes. The alkoxy group is named by adding the ending ‘oxy’ to the alkyl substituent, and this prefixes the name of the longest carbon chain.