Transition Metals

Transition Metals

Definition and Series:

  • Also known as ‘d-block’ elements, transition metals are defined as elements that have partially filled d orbitals.
  • Important transition metals include copper, iron, and nickel among others. All transition metals are found in the d-block of the periodic table.

General Properties and Differences:

  • Transition metals have typical metallic properties such as good conductivity of heat and electricity, and malleability.
  • Unlike group 1 and 2 metals, transition metals don’t react vigorously with water or oxygen.
  • These metals often exhibit multiple oxidation states which are due to the presence of electrons in the d orbital. This can result in a variety of different colours when they form complexes.

Colour and Transition Metal Complexes:

  • Each transition metal’s distinctive colour is due to d-d electronic transitions that absorb certain wavelengths of light.
  • The remaining light, when combined, forms the colour that we observe. For example, copper (II) sulphate is known for its characteristic blue colour.
  • These metals are also able to form complex ions with ligands. The complex ions can also display different colours depending on the metal and the ligand used.

Catalytic Properties:

  • Transition metals and their compounds often act as good catalysts. This is due to their ability to adopt multiple oxidation states and to form complexes.
  • For example, iron is a catalyst in the Haber process for making ammonia, and nickel is used for hydrogenation of alkenes.

Magnetic Properties:

  • Some transition metals, such as iron, cobalt, and nickel, are attracted to magnets and are said to be ferromagnetic.
  • This is due to the presence of unpaired electrons that generate magnetic fields.

Medical and Biological Importance:

  • Certain transition metals like copper and zinc are important for biological processes and required in trace amounts in the body.
  • Others, like platinum, are used in medicines such as those used to treat cancer.