Question

what is lanthanide ?​

Answer 1

Answer:

The lanthanide or lanthanoid series of chemical elements comprises the 15 metallic chemical elements with atomic numbers 57–71, from lanthanum through lutetium. These elements, along with the chemically similar elements scandium and yttrium, are often collectively known as the rare-earth elements.

Answer 2

The lanthanides are generally considered to be elements with atomic numbers 58-71 (lanthanum to lutetium). The lanthanide series is the group of elements in which the 4f sublevel is being filled. All of these elements are metals (specifically, transition metals).