Lanthanoids

Actinoids

1.The electronic configuration of lanthanoids is [Xe]⁵⁴ 4f^1-14

1.The electronic configuration of actinoids is [Rn]⁸⁶ 5f^1-14 6d^0-1 7s²

2. They show limited oxidation states (+2, +3, +4) out of which +3 is most common. This is because of the large energy gap between 4f and 5d subshells.

2. Actinoids show a large number of oxidation states (+3,+4,+5,+6,+7) because of the small energy gap between 5f, 6d, and 7s subshells.

3. The first few members of the series are quite reactive, almost like calcium with increasing atomic no. their behaviour becomes similar to that of aluminium

3.They are highly reactive metals especially in the finely divided state. When they are added to boiling water they give a mixture of oxide and hydride.