1. Last electron enter in “f” orbitals
2. Electronic configuration: (n-2)f(1-14) (n-1)d(0-1) ns2 n = 6-7
3. 4f series called Lanthanoids (58 Ce to 71 Lu)
4. 5f series called Actenoids (90 Th to 103 Lr)
5. After atomic number 92 U, they all are synthetic elements (61-Pm), called transuranic elements
6. They are heavy metal, having high boiling point and melting point
7. They show variable oxidation state
8. They form coordination compounds
9. They form colored compounds
10. all actinides are radioactive