Question

What are lanthanoides and actinoides?


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Answer 1

Explanation:

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Answer 2

in group three of the sixth Period there is a set of element with atomic number 57 271 beginning with lanthanum this element are known as a length side also known as rare Earth element

in group 3 of the period seventh is a set of elements atomic number 89 to 103 beginning with actinium this element are known as actinides.This are also known as radioactive element