Transition metals are a group of elements located in the d-block of the periodic table. They are characterised by their partially filled d-orbitals in the electron configuration, which gives rise to their unique properties. The general electronic configuration of transition metals can be represented as [noble gas] (n-1)d(1-10) ns(1-2), where "n" represents the principal quantum number.
Influence on Properties:
1. Variable Oxidation States: The presence of partially filled d-orbitals allows transition metals to exhibit multiple oxidation states. This ability to gain or lose different numbers of electrons makes them versatile in forming various compounds and participating in redox reactions.
2. Catalytic Activity: Transition metals are excellent catalysts due to their ability to adopt different oxidation states during a reaction. They provide an active surface for reactants to bind and undergo chemical transformations.
3. Formation of Complexes: Transition metals readily form coordination complexes with ligands. The partially filled d-orbitals allow them to accommodate ligands and form stable coordination compounds through d-d orbital interactions.
4. Coloration: Transition metal compounds often exhibit vibrant colours due to d-d electron transitions. When light is absorbed, electrons move between different d-orbitals, causing the compound to appear coloured.
5. High Density and Melting Points: Transition metals generally have high densities and melting points due to the strong metallic bonding arising from the delocalization of d-electrons.
6. Paramagnetism: Transition metals are often paramagnetic because of unpaired electrons in their d-orbitals. This property makes them attracted to magnetic fields.
Question:
Discuss the significance of transition metals and their properties in various applications.
Answer:
The properties of transition metals play a crucial role in numerous applications across various industries. Some key applications include:
1. Industrial Catalysis: Transition metals such as platinum, palladium, and rhodium are widely used as catalysts in industrial processes, including petroleum refining, environmental protection, and pharmaceutical production.
2. Alloys and Metallurgy: Transition metals are essential components in various alloys, improving the mechanical properties of materials. For instance, steel, which contains iron as the base metal with added transition metals like chromium, nickel, and manganese, exhibits enhanced strength and corrosion resistance.
3. Electronics and Magnets: Transition metals, particularly iron, cobalt, and nickel, are vital in electronics and magnet manufacturing. They are used to create permanent magnets and magnetic storage devices like hard drives.
4. Jewellery and Artefacts: Transition metals, especially gold, silver, and copper, are used in jewellery and artefacts due to their attractive colours and resistance to tarnishing.
5. Medical Applications: Transition metals find applications in medicine and healthcare. For example, platinum-based drugs like cisplatin are used in chemotherapy to treat cancer. Iron is essential in haemoglobin, responsible for oxygen transport in the blood.
6. Photovoltaic Cells: Transition metals like copper and cadmium are used in photovoltaic cells for solar energy conversion.
7. Environmental Remediation: Transition metals are used in environmental remediation to remove pollutants from water and air. They participate in catalytic reactions that break down harmful substances.
The unique properties of transition metals, such as their variable oxidation states, catalytic activity, and ability to form coordination complexes, make them versatile and indispensable in various technological advancements and everyday applications.
