how many os are in al₂(so₄)₃

Explanation:

Step1: Analyze the sulfate - ion part

In the formula $\text{Al}_2(\text{SO}_4)_3$, the sulfate ion is $\text{SO}_4$. Each sulfate ion has 4 oxygen atoms.

Step2: Consider the number of sulfate ions

There are 3 sulfate ions in $\text{Al}_2(\text{SO}_4)_3$ as indicated by the sub - script 3 outside the parentheses.

Step3: Calculate the total number of oxygen atoms

We multiply the number of oxygen atoms in one sulfate ion (4) by the number of sulfate ions (3). So the total number of oxygen atoms is $4\times3 = 12$.

Answer:

12