The `f`-block elements of the periodic table contains those element in which

Options

A. Only `4f` orbitals are progressively filled in `6th` period.
B. Only `5f` orbitals are progressively filled in `7th` period.
C. `4f` and `5f` orbitals are progressivley filled in `6th` and `7th` period respectively.
D. none

Answer

C

Explanation

Electronic configuration of f-block element`(n-2)f^(1-14),(n-1),ns^(2)` f-block start with `6^(th)` period `(n=6)`