Periodicity examines the trends in chemical and physcial properties across and down the periodic table of elements. The trends are 'periodic', in that they repeat themselves. The periodic table of elements is arranged in order of proton number, and in accordance with our model of the electronic structure of atoms.

  • Coloured complexes

    Coloured compounds arise in d-block elements due to the splitting in energy of the d-sub-levels when ligands surround the central metal ion.

  • First-row d-block elements

    The first-row of the d-block elements form coloured compounds, often make good catalysts and have variable oxidation states.

  • Periodic table

    This section explains the classification of elements in the periodic table. The arrangement of an element in the periodic table helps to predict its electron configuration. Practise with the questions to confirm your understanding.

  • Periodic trends

    Periodicity refers to the pattern in the change in the properties of elements across a period. The position of an element in the Periodic Table allows scientists to make predictions about its physical and chemical properties.