General properties of the transition elements
- They are very hard and strong metals and are good conductors of heat and electricity
- They have very high melting points and are highly dense metals
- Eg the melting point of titanium is 1,688ºC whereas potassium melts at only 63.5ºC, slightly warmer than the average cup of hot chocolate!
- The transition metals form coloured compounds and often have more than one oxidation state
- Transition metals are often used as catalysts
Although scandium and zinc are in the transition metal area of the Periodic table, they are not considered transition elements as they do not form coloured compounds and have only one oxidation state.
Variable oxidation states
- The transition elements have more than one oxidation state, as they can lose a different number of electrons, depending on the chemical environment they are in
- Iron for example can lose two electrons to form Fe2+ or three electrons to form Fe3+
- Compounds containing transition elements in different oxidation states will have different properties and colours
Uses of the transition elements
- The transition elements are used extensively as catalysts due to their ability to interchange between a range of oxidation states
- This allows them to form complexes with reagents which can easily donate and accept electrons from other chemical species within a reaction system
- They are used in medicine and surgical applications such as limb and joint replacement (titanium is often used for this as it can bond with bones due to its high biocompatibility)
- They are also used to form coloured compounds in dyes and paints, stained glass jewellery