Name: Actinium
Symbol: Ac
Atomic Number: 89
Atomic Mass: (227)
Standard State: solid
Group name: Actinoids
Period in Periodic Table: 7 (actinoid)
Color: silvery
Classification: metallic

Actinium was discovered by Andre Debierne at 1899 in France. Name Origin: from the Greek word "aktinos" meaning "ray".

Actinium is dangerously radioactive. The chemical behaviour of actinium is similar to that of the rare earths, particularly lanthanum. It is found naturally in uranium ores and actinium is 150 times more radioactive than radium.
Actinium was discovered by Andre Debierne in 1899 and independently by F. Giesel in 1902, both of whom obtained it while working on separation techniques for rare earth oxides.