* Identify the subscripts: The subscript "2" after the parenthesis indicates that there are two nitrate (NO₃) groups in the molecule. The subscript "3" in the nitrate group indicates that there are three oxygen atoms in each nitrate group.
* Multiply to find the total: To find the total number of oxygen atoms, multiply the number of nitrate groups by the number of oxygen atoms per nitrate group: 2 nitrate groups * 3 oxygen atoms/nitrate group = 6 oxygen atoms.
Therefore, there are 6 oxygen atoms in Ba(NO₃)₂.
