When studying the halogens (group 17) on the periodic table, how does the number of the valence electrons change as the energy level is increased? a) the total number of valence electrons does not change, it remains 7. b) the total number of valence electrons does not change, it remains 1. c) the total number of valence electrons increases by 1 with each energy level. d) the total number of valence electrons decreases by 1 with each energy level.

The correct answer is Option A.

Explanation:

Elements that are present in Group 17 are Fluorine (F), Chlorine (Cl), Bromine (Br), Iodine (I) and Astatine (At).

The general electronic configuration for these elements are:

Where,

n = principle quantum number or the number of period to which the element belongs.

In the electronic configuration, the noble gas which is present in the proceeding period.

The valence electrons are defined as the number of electrons which are present in the outermost shell.

Number of valence electrons for this group are 7. In a period, the valence electrons remains constant.

Hence, the correct answer is Option A.