Question

What is the valence shell electronic configuration of an element belonging to group 8a and period 4?

a) 4s^2 4p^4
b) 3s^2 3p^6
c) 4s^2 3d^10
d) 5s^2 5p^6

Answer 1

The valence shell electronic configuration of an element belonging to group 8a and period 4 is 4s^2 4p^4. Group number indicates the number of valence electrons and period number indicates the principal energy level.

Step-by-step explanation:

The valence shell electronic configuration of an element belonging to group 8a and period 4 is 4s^2 4p^4 (option a). The group number on the periodic table indicates the number of valence electrons in the element. Group 8a (also known as group 18 or the noble gases) has 8 valence electrons, except for helium which has only 2.

Period number indicates the highest principal energy level the element's valence electrons occupy, so for an element in period 4, the valence electrons occupy the 4th principal energy level.