The F Block Elements
The electronic configurations of the actinides utilize the f sublevel. Depending on your interpretation of the periodicity of the elements, the series begins with actinium, thorium, or even lawrencium. The actinides (An) are prepared by reduction of AnF3 or AnF4 with vapors of Li, Mg, Ca, or Ba at 1100 - 1400°C.
Common Properties of the Actinides
Actinides share the following common properties:
- All are radioactive.
- Actinides are highly electropositive.
- The metals tarnish readily in air.
- Actinides are very dense metals with distinctive structures. Numerous allotropes may be formed (plutonium has at least 6 allotropes!).
- They react with boiling water or dilute acid to release hydrogen gas.
- Actinides combine directly with most nonmetals.
