Lanthanoids are

Options

A. 14 elements in the sixth period (atomic no = 90 to 103) that are filling 4f sublevel
B. 14 elements in the seventh period (atomic no = 90 to 103) that are filling 5f sublevel
C. 14 elements in the 6th period (atomic no = 58 to 71) that are filling the 4f sublevel
D. 14 elements in the 7th period (atomic no = 50 to 71) that are filling the 4f sublevel

Answer

C

Explanation

Lanthanons or lanthanides are 14 elements `(Z = 58 to 71)` of group '3' and sixth period. They are characterized by the filling up the antepenulimate 4f energy l,evels. Actually, they are placed below the periodic table in horizontal row as lanthanide series.