How do transition metals differ in atomic structure from other elements?

Transition metals differ from other elements due to their ability to form multiple oxidation states and complex ions.

Transition metals are found in the middle of the periodic table, specifically in groups 3 to 12. They are unique in their atomic structure, which is characterised by the presence of electrons in the d-orbitals. This is different from other elements, such as those in groups 1 and 2 (the alkali and alkaline earth metals), which have their outermost electrons in the s-orbitals, or those in groups 13 to 18, which have their outermost electrons in the p-orbitals.

The presence of electrons in the d-orbitals allows transition metals to form multiple oxidation states. This is because these electrons are relatively easy to remove, allowing the metal to lose different numbers of electrons and thus form ions with different charges. For example, iron can form both Fe2+ and Fe3+ ions. This is a key difference from other elements, which typically form ions with a single, fixed charge.

Another unique feature of transition metals is their ability to form complex ions. These are ions in which the metal ion is surrounded by other ions or molecules, known as ligands. The ability to form complex ions is due to the empty d-orbitals in the transition metals, which can accept pairs of electrons from the ligands. This is a property not seen in other groups of elements.

In summary, the atomic structure of transition metals, characterised by the presence of electrons in the d-orbitals, gives them unique chemical properties. These include the ability to form multiple oxidation states and complex ions, distinguishing them from other elements in the periodic table.