Question

Complete the following suitably:

In any vertical column of elements in a subgroup of the Periodic Table, as you go from top to bottom.

The number of electronic shells ______.

Answer 1

• Modern periodic table is the arrangement or organization of elements on the basis of increasing atomic number in 7 horizontal rows and 18 vertical columns.
• Horizontal rows are termed as Periods while the vertical columns are termed as Groups.
• Count of shells in any element can be predicted by its Period number. Example, elements in Period 2 have 2 shells to accommodate the required number of electrons.
• On moving down the group, the period number of elements increases by 1 unit, and therefore, the number of electronic shells also increases by 1 unit.
• Example, Fluorine (F) and Chlorine (Cl) both belong to the same Group (Group 17) but Fluorine lies above Chlorine in the Group.
• Fluorine lies in the second Period and therefore, it has two electronic shells while Chlorine (Cl) lies in the third period and therefore, it has three electronic shells for the accommodation of the electrons.
• Hence, the number of electronic shells increases by 1.