Chemistry · Chapter 2

Ion Pair Builder

An ionic formula is a charge balance. Add ions to each side until the totals cancel, then read the formula unit off the counts.

The charge balance it tips until the charges cancel

Charge balance between cations and anions

The beam is a picture of charge, not of mass. It levels out when the total positive charge equals the total negative charge. That is the only condition an ionic formula has to meet.

Your formula

NaCl balanced
sodium chloride One 1+ ion and one 1− ion cancel.

Pick your ions

Cation
Anion
How many of each
How to do it by hand
Use the lowest common multiple
Take the two charge sizes and find their lowest common multiple. Divide it by each charge to get the counts. Then check that the counts share no factor above 1.