Question

Lanthanoids are
(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 sixth period (atomic no. = 58 to 71) that are filling 4f sublevel
(d) 14 elements in the seventh period (atomic no. = 58 to 71) that are filling 4f sublevel

Answer 1

C IS CORRECT ANSWER ...............

Answer 2

option (c) is the correct answer...