The Transition Elements (d-Block)
Transition elements, spanning groups 3-12 on the periodic table, are characterized by the progressive filling of the d orbitals. This section elaborates upon their unique properties that arise from the presence of unfilled d electrons, which confer distinct metallic attributes such as metallic luster, malleability, and ductility.
Key Points Covered:
- Electronic Configurations: Transition elements typically follow the electronic configuration of (n-1)d¹⁻⁵ ns¹², with notable exceptions like chromium (3d⁵4s¹) and copper (3d¹⁰4s¹).
- Oxidation States: These elements showcase variable oxidation states, which are due to the promotion of electrons among the d and s orbitals. For example, manganese can exhibit oxidation states from +2 to +7.
- Physical Properties: Transition metals have high melting and boiling points, which result from strong metallic bonds facilitated by d electrons.
- Chemical Reactivity: Their ability to exist in multiple oxidation states leads to a rich chemistries, such as the formation of colored ions and complexes, making them valuable in catalysis and various chemical reactions.
- Applications: Transition elements play pivotal roles in industries as catalysts and in alloy manufacturing.
Overall, this section explores the transition metals' crucial role in both nature and human applications, highlighting their diverse properties and functionalities.