# (solved)Question 3.4 of NCERT Class XI Chemistry Chapter 3

On the basis of quantum numbers, justify that the sixth period of the periodic table should have 32 elements.
(Rev. 03-Aug-2022)

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### Question 3.4NCERT Class XI Chemistry

On the basis of quantum numbers, justify that the sixth period of the periodic table should have 32 elements.

### Solution in Detail(video solution below this)

The orbitals start filling from $\displaystyle 6s^1$ and continue till $\displaystyle 6p^6$.

the aufbau order is $\displaystyle 6s \lt 4f \lt 5d \lt 6p$

total orbitals 6s(1) + 4f(7) + 5d(5) + 6p(3) = 16.

by Pauli Exclusion Principle each orbital can have a maximum of 2 electrons.

$\displaystyle \therefore$ total electrons = 16 x 2 = 32.

which justifies that period 6 can have 32 elements.

### Video Explanation

Please watch this youtube video for a quick explanation of the solution: