Question

bromine is found in group 17 and period 4. what does this tell you?
a. it has 7 valence electrons and 4 electron shells.
b. it has 17 valence electrons and 4 electron shells.
c. it has 4 valence electrons and 7 electron shells.

Explanation:

In the periodic table, the group number (for main - group elements) gives the number of valence electrons. Group 17 elements have 7 valence electrons. The period number gives the number of electron shells. Period 4 elements have 4 electron shells.

Answer:

A. It has 7 valence electrons and 4 electron shells.