Question
Wed April 15, 2015 By: Bosesreyan

What are lanthanides and actinides?

Expert Reply
Prachi Sawant
Thu April 16, 2015
The lanthanide or lanthanoid series comprises the fifteen elements with atomic numbers 57 through 71, fromlanthanum to lutetium. All lanthanides are f-block elements, corresponding to the filling of the 4f electron shell.
 
The actinide or actinoid series encompasses the 15 chemical elements that lie between actinium and lawrencium included on the periodic table, with atomic numbers 89 - 103. The actinoid series derives its name from the first element in the series, actinium, and ultimately from the Greek aktis, "ray," reflecting the elements' radioactivity.
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