Chapter 5, Problem 1E

Occasionally, we will see an ionic compound that has a $-1$ counterion. (Later we will find that $-1$ counterions are often more than spectators and take an active role in many reactions.)
a. What elements (other than H) on the periodic table are most likely to form a $-1$ anion?
b. Draw a Lewis structure for the ionic compound ${\text{NH}}_{\text{4}}\text{Cl}$ (Hint. One atom is a $-1$ counterion).