Question: In the sixth period, the orbitals that are filled are
$6 \mathrm{~s}, 5 \mathrm{f}, 6 \mathrm{~d}, 6 \mathrm{p}$
$6 \mathrm{~s}, 6 \mathrm{p}, 6 \mathrm{~d}, 6 \mathrm{f}$
$6 \mathrm{~s}, 5 \mathrm{~d}, 5 \mathrm{f}, 6 \mathrm{p}$
$6 \mathrm{~s}, 4 \mathrm{f}, 5 \mathrm{~d}, 6 \mathrm{p}$
Correct Option: , 4
Solution:
As per $(n+\ell)$ rule in $6^{\text {th }}$ period, order of orbitals filling is $6 \mathrm{~s}, 4 \mathrm{f}, 5 \mathrm{~d}, 6 \mathrm{p}$.
