Lanthanides And Actinides - F Block Elements
Lanthanides and actinides belong to the F block of the modern periodic table which makes up the inner transition metals. The two rows that are generally placed underneath the Periodic Table are called the lanthanide series and the actinide series. There are thirty total elements in the lanthanides and actinides series. They are called inner transition elements because of their placement in the periodic table due to their electron configurations.
The major difference between actinides and lanthanides is that actinoids are involved in the filling of 5f-orbitals whereas lanthanoids are involved in the filling of 4f- orbitals.
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