Elements in the lanthanide and Actinide series [duplicate]








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[Why is lanthanum a lanthanide and actinium an actinide?](/questions/7406/why-is-lanthanum-a-lanthanide-and-actinium-an-actinide)

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How many elements are there in lanthanide and Actinide series? My big doubt is does the 57th element Lanthanum and 89th element Actinium include in it? [![Click for the question I got](https://i.stack.imgur.com/Q07Va.jpg)](https://i.stack.imgur.com/Q07Va.jpg)


In some periodic table the entire 57-71 is given outside the box but in some of them only 58-71 is given outside the box. 




The arrangement of elements in periodic table is a subject of debate. There is no particular arrangement which is the best. This is the reason of confusion.


However, Concise Inorganic Chemistry by J.D. Lee mentions:



> 
> These four elements [Sc,Y,La,Ac] are sometimes grouped with the 14 lanthanides and called collectively the 'rare-earths'. This is a misnomer because the scandium group are d-block elements and the lanthanides are f-block elements.
> 
> 
> Pg 677, Concise Inorganic Chemistry, J.D. Lee, Blackwell Science Ltd, 1996.
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> 


So you can consider that the lanthanide and actinide group each contains 14 elements and Lanthanum and Actinium are d-block elements.


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