Question

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

Answer 1

According to Pauli's exclusion principle, each orbital can accommodate a maximum of 2 electrons. Thus, 16 orbitals can accommodate a maximum of 32electrons. Hence, the sixth period of the periodic table should have 32 elements.

Answer 2

In 6th period, electrons are filled in 6th energy shell.

The electrons are filled in the subshells following the sequence: 6s - 4f - 5d - 6p

Number of orbitals in the sub shells are:
6s : 1
4f : 7
5d : 5
6p : 3

Total orbitals = 1+7+5+3 = 16 orbitals

Each orbital can have maximum of 2 electrons. So total electrons that can be filled in the sixth period = 16 × 2 = 32

So we can accommodate 32 elements in the 6th period.