• the same functional group

• the same general formula

• members that differ from one to the next by a CH2- unit

• a consistent trend in physical properties with increasing molecular size

• similar chemical properties.

saturated hydrocarbons: hydrocarbons molecules in which al the carbon-carbon bonds are single covalent bonds

alkanes: a series of hydrocarbons; they are saturated compounds as they have only single bonds between carbon atoms in their structure

molecular formula: a formula that shows the actual number of atoms of each element present in a molecule of the compound

displayed formula: a representation of the structure of a compound that shows all the atoms and bonds in the molecule

alkenes: a series of hydrocarbons; they are unsaturated molecules as they have a C=C double bond somewhere in the chain

unsaturated hydrocarbons: hydrocarbons whose molecules contain at least one carbon-carbon double or triple bond

addition reaction: a reaction in which a simple molecule adds across the carbon-carbon double bond of an alkene

Alcohols: A homologous series of compounds with the -OH functional group. The simplest member of the series is methanol.

Carboxylic acid: A homologous series of compounds with the -COOH functional group. The simplest member of the series is methanoic acid.

• The product has two carbon atoms joined by a single bond. So, it is named after ethane.

• The molecule contains two bromine atoms. It is called dibromoethane.

• The bromine atoms are not both attached to the same carbon atom. One bromine atom is bonded to each carbon atom. The carbon atoms are numbered 1 and 2. The full name of the compound is 1,2-dibromoethane.