How do transition metals differ from other elements in the periodic table?

Transition metals differ from other elements as they can form compounds with variable oxidation states and complex ions.

Transition metals are a group of elements found in the middle of the periodic table, specifically in groups 3 to 12. They are unique in their ability to form compounds with variable oxidation states. This means that they can lose different numbers of electrons, and thus have different charges, when they form compounds. This is unlike other elements, which typically have fixed oxidation states. For example, iron can exist in both +2 and +3 oxidation states, which is why we have both iron(II) and iron(III) compounds.

Another key characteristic of transition metals is their ability to form complex ions. Complex ions are charged species that consist of a central metal ion surrounded by other atoms, ions or molecules, known as ligands. The ligands are attached to the central ion by coordinate bonds. This is a unique property of transition metals and is not seen in other groups of elements in the periodic table.

Transition metals also have other unique properties. They are generally hard and have high melting and boiling points, due to the strong metallic bonding. They are also good conductors of heat and electricity. Many transition metals and their compounds are coloured, which is due to the presence of d-electrons. These electrons can absorb certain wavelengths of light and then re-emit it, producing colour. This is different from other elements in the periodic table, which often form colourless compounds.

In summary, transition metals are unique in their ability to form compounds with variable oxidation states and complex ions. They also have other distinctive properties such as being hard, having high melting and boiling points, being good conductors of heat and electricity, and forming coloured compounds.