On the basis of quantum numbers, justify that the `6^(th)` period of the periodic table should have 32 elements.

Explanation

The atoms of 6 th period elements contain 6 orbits containing the electrons.
In the long form periodic table every period starts with the filling of new orbit. So sixth period starts with the filling of principal quantum number 6. The sixth period should end with the filling of p-sub-shell of the same orbit. Thus the outer electronic configuration of last element is `6s^(2) 6p^(6)`. Before the 6p orbital starts filling the subshells to be filled with electrons are 6s, 4f and 5d.
The electrons that can be filled in 6s are 2, 4f and 14, 5d and 10 and 6p are 6, a total of 32 electrons. Thus the number of elements that can present in the 6th period are 32 elements.