How do transition metals differ chemically from other metals?

Transition metals differ chemically from other metals due to their ability to form multiple oxidation states and coloured compounds.

Transition metals are a group of elements found in the middle of the periodic table. They are unique in their chemical properties, which set them apart from other metals. One of the key differences is their ability to form multiple oxidation states. This means that they can lose different numbers of electrons, resulting in different charges. For example, iron can exist in both +2 and +3 oxidation states, which are known as iron (II) and iron (III) respectively. This is in contrast to other metals, such as sodium or magnesium, which can only lose a fixed number of electrons and therefore have a single oxidation state.

Another distinctive feature of transition metals is their ability to form coloured compounds. This is due to the presence of d-electrons. When light shines on a transition metal compound, some wavelengths are absorbed as the d-electrons are excited to higher energy levels. The remaining light is then transmitted or reflected, and this is the colour we see. For instance, copper (II) sulphate is a bright blue colour, while potassium dichromate is orange. This is a stark contrast to compounds of other metals, which are often colourless or white.

Furthermore, transition metals are often good catalysts, meaning they can speed up chemical reactions without being used up themselves. This is because they can provide a surface for the reaction to take place on, and their variable oxidation states allow them to interact with a wide range of substances. For example, iron is used as a catalyst in the Haber process for making ammonia. This property is not commonly found in other metals.

In summary, transition metals are chemically distinct from other metals due to their ability to form multiple oxidation states, coloured compounds, and act as catalysts in chemical reactions.