Discuss the relation between the number of electron filled into the sub energy levels of an orbit and the maximum number of elements present in a period.

Explanation

Elements have been accommodated in these periods according to the following scheme.
1st period: The first main energy shell (K-shell) is completed. As the maximum capacit of K-shell is of 2 electrons, it consists of only two elements, hydrogen `(1s^(1))` and helium `(1s^(2))`.
2nd period: The second main energy shell is completed (i.e.,) 2s and 2p are completed. It includes eight elements from Li `(2s^(1))` to Ne `(2s^(2)2p^(6))`
3rd period: The 3s and 3p energy shells are completed. It includes also eight elements from `Na(3s^(1)) " to " Ar(3s^(2) 3p^(6))`.
4th period: The 4s, and 3d and 3p energy shells are completed. It includes 18 elements from `K(4s^(1))` to `Kr (3d^(10) 4s^(2) 4p^(6))`. It includes two s-block elements, ten d-block elements and six p-block elements.
5th period: The 5s, 4d and 5p energy shells are completed. It includes 18 elements from Rb (5s) to Xe `(4d^(10) 5s^(1) 5p^(6))`. Ist also includes two s-block elements, ten d-block elements and six p-block elements.
6th period: The 6s, 4f, 5d and 6p energy shells are completed. (i.e., ) it includes 32 elements from Cs `(6s^(1))` to `Rn (4f^(14) 5d^(10) 6s^(2) 6p^(6))`. It consists of two s-block elements, ten d-block elements, six p-block elements and fourteen f-block elements.
As this period can accommodate only 18 elements in the table, 14 members of 4f-series are separatelly accommodated in a horizontal row below the periodic table.
7th period: This period at present consists 26 elements. The 7s, 5f and 6d are completed (i.e.,) twenty six elements. Seven of the elements from atomic numbers 106 to 112 have recently been reported.