Provide an example of the properties of first row transition metals.

First row transition metals have variable oxidation states and form coloured compounds.

First row transition metals are elements in the d-block of the periodic table, including scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, and copper. These metals have partially filled d-orbitals, which allow them to form coloured compounds due to the absorption and reflection of light.

One of the key properties of first row transition metals is their ability to have variable oxidation states. This means that they can lose or gain electrons to form ions with different charges. For example, iron can have an oxidation state of +2 or +3, while copper can have an oxidation state of +1 or +2. This property makes these metals useful in a variety of biological and industrial processes.

Another important property of first row transition metals is their ability to form complex ions. These are ions in which a central metal ion is surrounded by a number of ligands, which are molecules or ions that donate electrons to the metal ion. Complex ions are often coloured and can be used in analytical chemistry to identify the presence of certain metals in a sample.

Overall, the properties of first row transition metals make them important in a variety of biological and industrial processes, from the transport of oxygen in the blood (iron) to the production of stainless steel (chromium).