Question

count the number of oxygen atoms in the following chemical formula. 4ca₂(no₃)₂

Explanation:

Step1: Analyze the formula inside the parentheses

In the formula \(4Ca_2(NO_3)_2\), for the part \((NO_3)_2\), the sub - script \(3\) indicates the number of oxygen atoms in one \(NO_3\) group. And the sub - script \(2\) outside the parentheses means there are \(2\) such \(NO_3\) groups. So the number of oxygen atoms in \((NO_3)_2\) is \(3\times2 = 6\).

Step2: Consider the coefficient outside

The coefficient \(4\) in front of \(Ca_2(NO_3)_2\) means there are \(4\) units of \(Ca_2(NO_3)_2\). Since each \(Ca_2(NO_3)_2\) has \(6\) oxygen atoms (from Step 1), the total number of oxygen atoms is \(4\times6=24\).

Answer:

24