Question

Which is the last member of the lanthanide series?

Answer 1

We have to know that the lanthanide arrangement of synthetic elements involves the $15$ metallic substance components with atomic numbers$57-71$, from lanthanum through lutetium. These components, alongside the chemically comparative components scandium and yttrium, are regularly all in all known as the uncommon earth components.

Complete answer:
The chemical formula Ln is utilized in everyday conversations of lanthanide science to allude to any lanthanide. Everything except one of the lanthanides is f-block components, relating to the filling of the 4f electron shell. There is some debate on whether lanthanum or lutetium is a d-block component, yet lutetium is generally thought about so by the individuals who study the matter; it is incorporated because of its substance similarities with the other $14$ . All lanthanide components structure trivalent cations, $L{n^{3 + }}$, whose science is to a great extent controlled by the ionic range, which diminishes consistently from lanthanum to lutetium.
They are called lanthanides in light of the fact that the components in the arrangement are artificially like lanthanum. Since "lanthanide" signifies "like lanthanum", it has been contended that lanthanum can't legitimately be a lanthanide, yet IUPAC recognizes its consideration dependent on normal use.
We have to know that the last member of the Lanthanide series is Lutetium. We can write the symbol of Lu and its atomic number is $71$. We can say that the atomic mass is $174.97g/mol$.

Note:
We have to remember that from element Cerium through Lutetium is known as the lanthanide series. We can separate these rare earth elements from other elements found in minerals through the process of separation with help of suitable reagents. They have the ability to form complexes with several organic compounds like beta-diketones, EDTA etc.