Question 6.7: Antacid tablets contain aluminum hydroxide, which treats aci...

STEP 1   Identify the cation and polyatomic ion (anion).

STEP 2   Balance the charges. The charge of 3+ is balanced by three OH^{-} ions.
1(3+) + 3(1-) = 0

STEP 3   Write the formula, cation first, using the subscripts from charge balance.
The formula for the compound is written by enclosing the formula of the hydroxide ion, OH^{-} , in parentheses and writing the subscript 3 outside the right parenthesis.
Al(OH)_{3}