Question

The series of elements having atomic number from 58 to 71 are called lanthanides.give reason

Answer 1

There's a mistake that Lanthanides Series don's have atomic number from 58 to 71 , instead it is from 57 to 71.

You should know that the Periodic Table is not of 2D view. It's a 3D table composite's of all the elements(except 58 to 71 & 90 to 103) as the plane and the atomic number (58 to 71) & (90 to 103) behind the plane.

The Lanthanides & Actinides series which goes back the plane has Lanthanum & Actinium as their first element and also on the plane. This might be the reason behind the naming in correspondence to their first element.