Halogens – chlorine, bromine and iodine
The non-metal elements found in group 7 of the periodic table are collectively known as the halogens. They include fluorine, ...
Group 1 – alkali metals
The metal elements in group 1 of the periodic table are known as the alkali metals. They include lithium, sodium, ...
Gases in the atmosphere
The air that we breathe on Earth is a mixture of different gaseous elements and compounds. The gases found in ...
Exothermic and endothermic reactions
During chemical reaction reactants (the substances we start with) are changed into the products (the substances we are left with ...
Extraction and uses of metals
Extraction and uses of metals Some unreactive metals such as gold are often found as the uncombined element, but most ...
Electrolysis
Electrolysis is the process by which a compound can be broken down or split into its elements by passing an ...
Energy level diagrams
An energy level diagram can be used to represent the energy changes that occur during a chemical reaction. They compare ...
Condensation polymers
Condensation polymers are produced as a result of a process known as condensation polymerisation. There are different types of condensation ...
Covalent bonding
When non-metals react with metals, a transfer of electrons takes place and an ionic bond is formed. When non-metals react ...
Chromatography
Chromatography is used to separate colours from mixtures of coloured substances such as inks, dyes and food colourings. A simple ...
Chemical tests
Testing for positively charged ions We can conduct experiments on positively charged ions (cations) to help us see which elements ...
Chemical solutions
When a solid (solute) is added to a liquid (solvent) the forces between the solute particles are overcome. This allows ...